Add --with-system-include-path etc.

Instead of hard-coding /usr/include, we now use the environment variable
PKG_CONFIG_SYSTEM_INCLUDE_PATH, defaulting to the argument of
./configure --with-system-include-path, which in turn defaults to
/usr/include.

Similarly, PKG_CONFIG_SYSTEM_LIBRARY_PATH defaults to /usr/lib or
/usr/lib:/usr/lib64 as appropriate.

(As currently implemented, this causes a behaviour change on Win32 -
the option -I/usr/include will now be filtered out.)

The intended usage is for Debian to configure pkg-config with
--with-system-include-path=/usr/include/$(DEB_HOST_GNU_TYPE):/usr/include
and the corresponding library path, for multiarch support
(<http://bugs.debian.org/482884>).

Based on work by Colin Walters <walters@verbum.org>

3 files changed, 84 insertions, 33 deletions

diff --git a/Makefile.am b/Makefile.am
index 5fde154..b1f51ee 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,7 +21,11 @@ EXTRA_DIST = $(m4_DATA) $(man_MANS) README.win32
 bin_PROGRAMS = pkg-config
 AM_CFLAGS=@WARN_CFLAGS@
 
-INCLUDES=-DPKG_CONFIG_PC_PATH="\"$(pc_path)\"" @GLIB_CFLAGS@ \
+INCLUDES= \
+	-DPKG_CONFIG_PC_PATH="\"$(pc_path)\"" \
+	-DPKG_CONFIG_SYSTEM_INCLUDE_PATH="\"$(system_include_path)\"" \
+	-DPKG_CONFIG_SYSTEM_LIBRARY_PATH="\"$(system_library_path)\"" \
+	@GLIB_CFLAGS@ \
 	$(popt_includes)
 
 pkg_config_SOURCES= \
diff --git a/configure.ac b/configure.ac
index 67577a7..ace5682 100644
--- a/configure.ac
+++ b/configure.ac
@@ -34,6 +34,31 @@ fi
 
 PKG_CONFIG_FIND_PC_PATH
 
+AC_MSG_CHECKING([for --with-system-include-path])
+AC_ARG_WITH(system_include_path,
+ [  --with-system-include-path    Avoid -I flags that add the given directories ],
+ [ system_include_path="$withval" ],
+ [ system_include_path="/usr/include" ])
+ AC_MSG_RESULT([$system_include_path])
+ AC_SUBST([system_include_path])
+
+AC_MSG_CHECKING([for --with-system-library-path])
+AC_ARG_WITH(system_library_path,
+ [  --with-system-library-path    Avoid -L flags that add the given directories ],
+ [ system_library_path="$withval" ],
+ [
+case "$libdir" in
+*lib64)
+  system_library_path="/usr/lib64:/usr/lib"
+  ;;
+*)
+  system_library_path="/usr/lib"
+  ;;
+esac
+])
+ AC_MSG_RESULT([$system_library_path])
+ AC_SUBST([system_library_path])
+
 #
 # Code taken from gtk+-2.0's configure.in.
 #
@@ -92,11 +117,6 @@ case "$host" in
 esac
 AC_MSG_RESULT([$native_win32])
 
-case "$libdir" in
-*lib64) AC_DEFINE(PREFER_LIB64,1,[Define if your native architecture defines libdir to be $prefix/lib64 instead of $prefix/lib.]) ;;
-*) : ;;
-esac
-
 if test "x$GLIB_CFLAGS" = "x" && test "x$GLIB_LIBS" = "x"; then
    AC_CHECK_PROGS([PKG_CONFIG], [pkg-config], [])
    if test -n $PKG_CONFIG && $PKG_CONFIG --exists glib-2.0; then
diff --git a/pkg.c b/pkg.c
index f76eda3..9ce31b2 100644
--- a/pkg.c
+++ b/pkg.c
@@ -744,7 +744,7 @@ verify_package (Package *pkg)
   GSList *conflicts_iter;
   GSList *system_dir_iter = NULL;
   int count;
-  const gchar *c_include_path;
+  const gchar *search_path;
 
   /* Be sure we have the required fields */
 
@@ -856,20 +856,26 @@ verify_package (Package *pkg)
   /* We make a list of system directories that gcc expects so we can remove
    * them.
    */
-#ifndef G_OS_WIN32
-  system_directories = g_slist_append (NULL, g_strdup ("/usr/include"));
-#endif
 
-  c_include_path = g_getenv ("C_INCLUDE_PATH");
-  if (c_include_path != NULL)
+  search_path = g_getenv ("PKG_CONFIG_SYSTEM_INCLUDE_PATH");
+
+  if (search_path == NULL)
     {
-      system_directories = add_env_variable_to_list (system_directories, c_include_path);
+      search_path = PKG_CONFIG_SYSTEM_INCLUDE_PATH;
     }
-  
-  c_include_path = g_getenv ("CPLUS_INCLUDE_PATH");
-  if (c_include_path != NULL)
+
+  system_directories = add_env_variable_to_list (system_directories, search_path);
+
+  search_path = g_getenv ("C_INCLUDE_PATH");
+  if (search_path != NULL)
     {
-      system_directories = add_env_variable_to_list (system_directories, c_include_path);
+      system_directories = add_env_variable_to_list (system_directories, search_path);
+    }
+
+  search_path = g_getenv ("CPLUS_INCLUDE_PATH");
+  if (search_path != NULL)
+    {
+      system_directories = add_env_variable_to_list (system_directories, search_path);
     }
 
   count = 0;
@@ -922,31 +928,52 @@ verify_package (Package *pkg)
   g_slist_foreach (system_directories, (GFunc) g_free, NULL);
   g_slist_free (system_directories);
 
-#ifdef PREFER_LIB64
-#define SYSTEM_LIBDIR "/usr/lib64"
-#else
-#define SYSTEM_LIBDIR "/usr/lib"
-#endif
+  system_directories = NULL;
+
+  search_path = g_getenv ("PKG_CONFIG_SYSTEM_LIBRARY_PATH");
+
+  if (search_path == NULL)
+    {
+      search_path = PKG_CONFIG_SYSTEM_LIBRARY_PATH;
+    }
+
+  system_directories = add_env_variable_to_list (system_directories, search_path);
+
   count = 0;
   iter = pkg->L_libs;
   while (iter != NULL)
     {
-      if (strcmp (iter->data, "-L" SYSTEM_LIBDIR) == 0 ||
-          strcmp (iter->data, "-L " SYSTEM_LIBDIR) == 0)
+      GSList *system_dir_iter = system_directories;
+
+      while (system_dir_iter != NULL)
         {
-          debug_spew ("Package %s has -L" SYSTEM_LIBDIR " in Libs\n",
-                      pkg->name);
-          if (g_getenv ("PKG_CONFIG_ALLOW_SYSTEM_LIBS") == NULL)
-            {              
-              iter->data = NULL;
-              ++count;
-              debug_spew ("Removing -L" SYSTEM_LIBDIR " from libs for %s\n", pkg->key);
+          gboolean is_system = FALSE;
+          const char *linker_arg = iter->data;
+          const char *system_libpath = system_dir_iter->data;
+
+          if (strncmp (linker_arg, "-L ", 3) == 0 &&
+              strcmp (linker_arg + 3, system_libpath) == 0)
+            is_system = TRUE;
+          else if (strncmp (linker_arg, "-L", 2) == 0 &&
+              strcmp (linker_arg + 2, system_libpath) == 0)
+            is_system = TRUE;
+          if (is_system)
+            {
+              debug_spew ("Package %s has -L %s in Libs\n",
+                          pkg->name, system_libpath);
+              if (g_getenv ("PKG_CONFIG_ALLOW_SYSTEM_LIBS") == NULL)
+                {
+                  iter->data = NULL;
+                  ++count;
+                  debug_spew ("Removing -L %s from libs for %s\n", system_libpath, pkg->key);
+                  break;
+                }
             }
+          system_dir_iter = system_dir_iter->next;
         }
-
       iter = iter->next;
     }
-#undef SYSTEM_LIBDIR
+  g_slist_free (system_directories);
 
   while (count)
     {