Greg Jandl to SDL

I did some digging, and I think I've found a better solution. By
including some additional .m4 macros in the acinclude directory
(http://www.gnu.org/software/autoconf-archive/ax_check_compiler_flags.html,
http://www.gnu.org/software/autoconf-archive/ax_gcc_archflag.html and
http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html)
then using the patch below (same as previous patch + one line change
to configure.in), SDL will build correctly out of the box.

The arch can then be overridden by --with-gcc-arch=<arch> (most will
probably want to build with i686 there for general distribution) or
--without-gcc-arch, to disable setting the arch all together.

On my Atom netbook, I get -march=PentiumPro by default, which works
great, as does --with-gcc-arch=i686.

3 files changed, 370 insertions, 0 deletions

diff --git a/acinclude/ax_check_compiler_flags.m4 b/acinclude/ax_check_compiler_flags.m4
new file mode 100644
index 00000000..35bfd2a5
--- /dev/null
+++ b/acinclude/ax_check_compiler_flags.m4
@@ -0,0 +1,76 @@
+# ===========================================================================
+#  http://www.gnu.org/software/autoconf-archive/ax_check_compiler_flags.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_COMPILER_FLAGS(FLAGS, [ACTION-SUCCESS], [ACTION-FAILURE])
+#
+# DESCRIPTION
+#
+#   Check whether the given compiler FLAGS work with the current language's
+#   compiler, or whether they give an error. (Warnings, however, are
+#   ignored.)
+#
+#   ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
+#   success/failure.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2009 Matteo Frigo
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 9
+
+AC_DEFUN([AX_CHECK_COMPILER_FLAGS],
+[AC_PREREQ(2.59) dnl for _AC_LANG_PREFIX
+AC_MSG_CHECKING([whether _AC_LANG compiler accepts $1])
+dnl Some hackery here since AC_CACHE_VAL can't handle a non-literal varname:
+AS_LITERAL_IF([$1],
+  [AC_CACHE_VAL(AS_TR_SH(ax_cv_[]_AC_LANG_ABBREV[]_flags_[$1]), [
+      ax_save_FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
+      _AC_LANG_PREFIX[]FLAGS="$1"
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
+        AS_TR_SH(ax_cv_[]_AC_LANG_ABBREV[]_flags_[$1])=yes,
+        AS_TR_SH(ax_cv_[]_AC_LANG_ABBREV[]_flags_[$1])=no)
+      _AC_LANG_PREFIX[]FLAGS=$ax_save_FLAGS])],
+  [ax_save_FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
+   _AC_LANG_PREFIX[]FLAGS="$1"
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
+     eval AS_TR_SH(ax_cv_[]_AC_LANG_ABBREV[]_flags_[$1])=yes,
+     eval AS_TR_SH(ax_cv_[]_AC_LANG_ABBREV[]_flags_[$1])=no)
+   _AC_LANG_PREFIX[]FLAGS=$ax_save_FLAGS])
+eval ax_check_compiler_flags=$AS_TR_SH(ax_cv_[]_AC_LANG_ABBREV[]_flags_[$1])
+AC_MSG_RESULT($ax_check_compiler_flags)
+if test "x$ax_check_compiler_flags" = xyes; then
+	m4_default([$2], :)
+else
+	m4_default([$3], :)
+fi
+])dnl AX_CHECK_COMPILER_FLAGS
diff --git a/acinclude/ax_gcc_archflag.m4 b/acinclude/ax_gcc_archflag.m4
new file mode 100644
index 00000000..d37a9134
--- /dev/null
+++ b/acinclude/ax_gcc_archflag.m4
@@ -0,0 +1,215 @@
+# ===========================================================================
+#      http://www.gnu.org/software/autoconf-archive/ax_gcc_archflag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_GCC_ARCHFLAG([PORTABLE?], [ACTION-SUCCESS], [ACTION-FAILURE])
+#
+# DESCRIPTION
+#
+#   This macro tries to guess the "native" arch corresponding to the target
+#   architecture for use with gcc's -march=arch or -mtune=arch flags. If
+#   found, the cache variable $ax_cv_gcc_archflag is set to this flag and
+#   ACTION-SUCCESS is executed; otherwise $ax_cv_gcc_archflag is is set to
+#   "unknown" and ACTION-FAILURE is executed. The default ACTION-SUCCESS is
+#   to add $ax_cv_gcc_archflag to the end of $CFLAGS.
+#
+#   PORTABLE? should be either [yes] (default) or [no]. In the former case,
+#   the flag is set to -mtune (or equivalent) so that the architecture is
+#   only used for tuning, but the instruction set used is still portable. In
+#   the latter case, the flag is set to -march (or equivalent) so that
+#   architecture-specific instructions are enabled.
+#
+#   The user can specify --with-gcc-arch=<arch> in order to override the
+#   macro's choice of architecture, or --without-gcc-arch to disable this.
+#
+#   When cross-compiling, or if $CC is not gcc, then ACTION-FAILURE is
+#   called unless the user specified --with-gcc-arch manually.
+#
+#   Requires macros: AX_CHECK_COMPILER_FLAGS, AX_GCC_X86_CPUID
+#
+#   (The main emphasis here is on recent CPUs, on the principle that doing
+#   high-performance computing on old hardware is uncommon.)
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2008 Matteo Frigo
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 8
+
+AC_DEFUN([AX_GCC_ARCHFLAG],
+[AC_REQUIRE([AC_PROG_CC])
+AC_REQUIRE([AC_CANONICAL_HOST])
+
+AC_ARG_WITH(gcc-arch, [AS_HELP_STRING([--with-gcc-arch=<arch>], [use architecture <arch> for gcc -march/-mtune, instead of guessing])],
+	ax_gcc_arch=$withval, ax_gcc_arch=yes)
+
+AC_MSG_CHECKING([for gcc architecture flag])
+AC_MSG_RESULT([])
+AC_CACHE_VAL(ax_cv_gcc_archflag,
+[
+ax_cv_gcc_archflag="unknown"
+
+if test "$GCC" = yes; then
+
+if test "x$ax_gcc_arch" = xyes; then
+ax_gcc_arch=""
+if test "$cross_compiling" = no; then
+case $host_cpu in
+  i[[3456]]86*|x86_64*) # use cpuid codes, in part from x86info-1.7 by D. Jones
+     AX_GCC_X86_CPUID(0)
+     AX_GCC_X86_CPUID(1)
+     case $ax_cv_gcc_x86_cpuid_0 in
+       *:756e6547:*:*) # Intel
+          case $ax_cv_gcc_x86_cpuid_1 in
+	    *5[[48]]?:*:*:*) ax_gcc_arch="pentium-mmx pentium" ;;
+	    *5??:*:*:*) ax_gcc_arch=pentium ;;
+	    *6[[3456]]?:*:*:*) ax_gcc_arch="pentium2 pentiumpro" ;;
+	    *6a?:*[[01]]:*:*) ax_gcc_arch="pentium2 pentiumpro" ;;
+	    *6a?:*[[234]]:*:*) ax_gcc_arch="pentium3 pentiumpro" ;;
+	    *6[[9d]]?:*:*:*) ax_gcc_arch="pentium-m pentium3 pentiumpro" ;;
+	    *6[[78b]]?:*:*:*) ax_gcc_arch="pentium3 pentiumpro" ;;
+	    *6??:*:*:*) ax_gcc_arch=pentiumpro ;;
+            *f3[[347]]:*:*:*|*f4[1347]:*:*:*)
+		case $host_cpu in
+                  x86_64*) ax_gcc_arch="nocona pentium4 pentiumpro" ;;
+                  *) ax_gcc_arch="prescott pentium4 pentiumpro" ;;
+                esac ;;
+            *f??:*:*:*) ax_gcc_arch="pentium4 pentiumpro";;
+          esac ;;
+       *:68747541:*:*) # AMD
+          case $ax_cv_gcc_x86_cpuid_1 in
+	    *5[[67]]?:*:*:*) ax_gcc_arch=k6 ;;
+	    *5[[8d]]?:*:*:*) ax_gcc_arch="k6-2 k6" ;;
+	    *5[[9]]?:*:*:*) ax_gcc_arch="k6-3 k6" ;;
+	    *60?:*:*:*) ax_gcc_arch=k7 ;;
+	    *6[[12]]?:*:*:*) ax_gcc_arch="athlon k7" ;;
+	    *6[[34]]?:*:*:*) ax_gcc_arch="athlon-tbird k7" ;;
+	    *67?:*:*:*) ax_gcc_arch="athlon-4 athlon k7" ;;
+	    *6[[68a]]?:*:*:*)
+	       AX_GCC_X86_CPUID(0x80000006) # L2 cache size
+	       case $ax_cv_gcc_x86_cpuid_0x80000006 in
+                 *:*:*[[1-9a-f]]??????:*) # (L2 = ecx >> 16) >= 256
+			ax_gcc_arch="athlon-xp athlon-4 athlon k7" ;;
+                 *) ax_gcc_arch="athlon-4 athlon k7" ;;
+	       esac ;;
+	    *f[[4cef8b]]?:*:*:*) ax_gcc_arch="athlon64 k8" ;;
+	    *f5?:*:*:*) ax_gcc_arch="opteron k8" ;;
+	    *f7?:*:*:*) ax_gcc_arch="athlon-fx opteron k8" ;;
+	    *f??:*:*:*) ax_gcc_arch="k8" ;;
+          esac ;;
+	*:746e6543:*:*) # IDT
+	   case $ax_cv_gcc_x86_cpuid_1 in
+	     *54?:*:*:*) ax_gcc_arch=winchip-c6 ;;
+	     *58?:*:*:*) ax_gcc_arch=winchip2 ;;
+	     *6[[78]]?:*:*:*) ax_gcc_arch=c3 ;;
+	     *69?:*:*:*) ax_gcc_arch="c3-2 c3" ;;
+	   esac ;;
+     esac
+     if test x"$ax_gcc_arch" = x; then # fallback
+	case $host_cpu in
+	  i586*) ax_gcc_arch=pentium ;;
+	  i686*) ax_gcc_arch=pentiumpro ;;
+        esac
+     fi
+     ;;
+
+  sparc*)
+     AC_PATH_PROG([PRTDIAG], [prtdiag], [prtdiag], [$PATH:/usr/platform/`uname -i`/sbin/:/usr/platform/`uname -m`/sbin/])
+     cputype=`(((grep cpu /proc/cpuinfo | cut -d: -f2) ; ($PRTDIAG -v |grep -i sparc) ; grep -i cpu /var/run/dmesg.boot ) | head -n 1) 2> /dev/null`
+     cputype=`echo "$cputype" | tr -d ' -' |tr $as_cr_LETTERS $as_cr_letters`
+     case $cputype in
+         *ultrasparciv*) ax_gcc_arch="ultrasparc4 ultrasparc3 ultrasparc v9" ;;
+         *ultrasparciii*) ax_gcc_arch="ultrasparc3 ultrasparc v9" ;;
+         *ultrasparc*) ax_gcc_arch="ultrasparc v9" ;;
+         *supersparc*|*tms390z5[[05]]*) ax_gcc_arch="supersparc v8" ;;
+         *hypersparc*|*rt62[[056]]*) ax_gcc_arch="hypersparc v8" ;;
+         *cypress*) ax_gcc_arch=cypress ;;
+     esac ;;
+
+  alphaev5) ax_gcc_arch=ev5 ;;
+  alphaev56) ax_gcc_arch=ev56 ;;
+  alphapca56) ax_gcc_arch="pca56 ev56" ;;
+  alphapca57) ax_gcc_arch="pca57 pca56 ev56" ;;
+  alphaev6) ax_gcc_arch=ev6 ;;
+  alphaev67) ax_gcc_arch=ev67 ;;
+  alphaev68) ax_gcc_arch="ev68 ev67" ;;
+  alphaev69) ax_gcc_arch="ev69 ev68 ev67" ;;
+  alphaev7) ax_gcc_arch="ev7 ev69 ev68 ev67" ;;
+  alphaev79) ax_gcc_arch="ev79 ev7 ev69 ev68 ev67" ;;
+
+  powerpc*)
+     cputype=`((grep cpu /proc/cpuinfo | head -n 1 | cut -d: -f2 | cut -d, -f1 | sed 's/ //g') ; /usr/bin/machine ; /bin/machine; grep CPU /var/run/dmesg.boot | head -n 1 | cut -d" " -f2) 2> /dev/null`
+     cputype=`echo $cputype | sed -e 's/ppc//g;s/ *//g'`
+     case $cputype in
+       *750*) ax_gcc_arch="750 G3" ;;
+       *740[[0-9]]*) ax_gcc_arch="$cputype 7400 G4" ;;
+       *74[[4-5]][[0-9]]*) ax_gcc_arch="$cputype 7450 G4" ;;
+       *74[[0-9]][[0-9]]*) ax_gcc_arch="$cputype G4" ;;
+       *970*) ax_gcc_arch="970 G5 power4";;
+       *POWER4*|*power4*|*gq*) ax_gcc_arch="power4 970";;
+       *POWER5*|*power5*|*gr*|*gs*) ax_gcc_arch="power5 power4 970";;
+       603ev|8240) ax_gcc_arch="$cputype 603e 603";;
+       *) ax_gcc_arch=$cputype ;;
+     esac
+     ax_gcc_arch="$ax_gcc_arch powerpc"
+     ;;
+esac
+fi # not cross-compiling
+fi # guess arch
+
+if test "x$ax_gcc_arch" != x -a "x$ax_gcc_arch" != xno; then
+for arch in $ax_gcc_arch; do
+  if test "x[]m4_default([$1],yes)" = xyes; then # if we require portable code
+    flags="-mtune=$arch"
+    # -mcpu=$arch and m$arch generate nonportable code on every arch except
+    # x86.  And some other arches (e.g. Alpha) don't accept -mtune.  Grrr.
+    case $host_cpu in i*86|x86_64*) flags="$flags -mcpu=$arch -m$arch";; esac
+  else
+    flags="-march=$arch -mcpu=$arch -m$arch"
+  fi
+  for flag in $flags; do
+    AX_CHECK_COMPILER_FLAGS($flag, [ax_cv_gcc_archflag=$flag; break])
+  done
+  test "x$ax_cv_gcc_archflag" = xunknown || break
+done
+fi
+
+fi # $GCC=yes
+])
+AC_MSG_CHECKING([for gcc architecture flag])
+AC_MSG_RESULT($ax_cv_gcc_archflag)
+if test "x$ax_cv_gcc_archflag" = xunknown; then
+  m4_default([$3],:)
+else
+  m4_default([$2], [CFLAGS="$CFLAGS $ax_cv_gcc_archflag"])
+fi
+])
diff --git a/acinclude/ax_gcc_x86_cpuid.m4.htm b/acinclude/ax_gcc_x86_cpuid.m4.htm
new file mode 100644
index 00000000..7d46fee0
--- /dev/null
+++ b/acinclude/ax_gcc_x86_cpuid.m4.htm
@@ -0,0 +1,79 @@
+# ===========================================================================
+#     http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_GCC_X86_CPUID(OP)
+#
+# DESCRIPTION
+#
+#   On Pentium and later x86 processors, with gcc or a compiler that has a
+#   compatible syntax for inline assembly instructions, run a small program
+#   that executes the cpuid instruction with input OP. This can be used to
+#   detect the CPU type.
+#
+#   On output, the values of the eax, ebx, ecx, and edx registers are stored
+#   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
+#   ax_cv_gcc_x86_cpuid_OP.
+#
+#   If the cpuid instruction fails (because you are running a
+#   cross-compiler, or because you are not using gcc, or because you are on
+#   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
+#   is set to the string "unknown".
+#
+#   This macro mainly exists to be used in AX_GCC_ARCHFLAG.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2008 Matteo Frigo
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 7
+
+AC_DEFUN([AX_GCC_X86_CPUID],
+[AC_REQUIRE([AC_PROG_CC])
+AC_LANG_PUSH([C])
+AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
+     int op = $1, eax, ebx, ecx, edx;
+     FILE *f;
+      __asm__("cpuid"
+        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
+        : "a" (op));
+     f = fopen("conftest_cpuid", "w"); if (!f) return 1;
+     fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
+     fclose(f);
+     return 0;
+])],
+     [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
+     [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
+     [ax_cv_gcc_x86_cpuid_$1=unknown])])
+AC_LANG_POP([C])
+])