cerbero, config/android, openssl: Don't pass the Android toolchain path wholesale

In !1191 (commit 643087f3f09fd637b29335efb608ac7a82031ecf), the removal of GCC
support relied on making the Android compiler available to all processes. This
fixed accessing the host's compiler for Meson based builds like fribidi's, and
also allowed OpenSSL to build, but there was a hidden side effect: it broke
Rust's ability to compile build scripts because the linker it finds (LLVM 14
from the NDK) no longer supports `--no-add-needed` [1] [2].

A more Meson-ese fix is to pass the toolchain as a constant in the native file,
and fill the path in manually. This also needs to be injected manually into the
`PATH` for OpenSSL as that's how its configure script consumes the toolchain.

[1]: https://github.com/llvm/llvm-project/issues/54756
[2]: https://github.com/llvm/llvm-project/commit/815a1207bfe121c8dcf3804a4f4638e580f63519

Part-of: <https://gitlab.freedesktop.org/gstreamer/cerbero/-/merge_requests/1368>

3 files changed, 13 insertions, 4 deletions

diff --git a/cerbero/build/build.py b/cerbero/build/build.py
index efdb4b71..0247dff1 100644
--- a/cerbero/build/build.py
+++ b/cerbero/build/build.py
@@ -725,6 +725,9 @@ cpu_family = '{cpu_family}'
 cpu = '{cpu}'
 endian = '{endian}'
 
+[constants]
+toolchain = '{toolchain}'
+
 [properties]
 {extra_properties}
 
@@ -976,6 +979,7 @@ class Meson (Build, ModifyEnvBase) :
                 cpu_family=self._get_target_cpu_family(),
                 # Assume all supported target archs are little endian
                 endian='little',
+                toolchain='',
                 CC=cc,
                 CXX=cxx,
                 OBJC=objc,
@@ -1008,9 +1012,9 @@ class Meson (Build, ModifyEnvBase) :
             objc = cc
             objcxx = cxx
         elif self.config.target_platform == Platform.ANDROID:
-            cc = ['clang']
-            cxx = ['clang++']
-            ar = ['llvm-ar']
+            cc = "toolchain / 'clang'"
+            cxx = "toolchain / 'clang++'"
+            ar = "toolchain / 'llvm-ar'"
             objc = cc
             objcxx = cxx
         else:
@@ -1026,6 +1030,7 @@ class Meson (Build, ModifyEnvBase) :
                 cpu=self.config.arch,
                 cpu_family=self.config.arch,
                 endian='little',
+                toolchain=self.get_env('ANDROID_NDK_TOOLCHAIN_BIN', ''),
                 CC=cc,
                 CXX=cxx,
                 OBJC=objc,
@@ -1051,6 +1056,7 @@ class Meson (Build, ModifyEnvBase) :
                 cpu=self.config.arch,
                 cpu_family=self.config.arch,
                 endian='little',
+                toolchain='',
                 CC=false,
                 CXX=false,
                 OBJC=false,
diff --git a/config/android.config b/config/android.config
index bdbc7dbb..611a5751 100644
--- a/config/android.config
+++ b/config/android.config
@@ -109,6 +109,7 @@ env.pop('RUSTFLAGS', None)
 
 # Android NDK path
 env['ANDROID_NDK_HOME'] = toolchain_prefix
+env['ANDROID_NDK_TOOLCHAIN_BIN'] = llvm_toolchain_path
 
 # 'universal' is set by cerbero itself when building under a universal regime
 # so that we can construct different paths to include/lib directories to where
@@ -188,7 +189,7 @@ env['NM']= llvm_cmd('llvm-nm')
 env['STRIP']= llvm_cmd('llvm-strip')
 env['OBJCOPY']= llvm_cmd('llvm-objcopy')
 
-env['PATH'] = f'{llvm_toolchain_path}:{spirv_toolchain_path}:{env["PATH"]}'
+env['PATH'] = f'{spirv_toolchain_path}:{env["PATH"]}'
 # For the libc.so dependency in i686-linux-android-as
 if target_arch == Architecture.X86:
     extra_lib_path = f'{sysroot}/usr/lib'
diff --git a/recipes/openssl.recipe b/recipes/openssl.recipe
index 77c50d56..dfc9572a 100644
--- a/recipes/openssl.recipe
+++ b/recipes/openssl.recipe
@@ -181,6 +181,8 @@ class Recipe(recipe.Recipe):
 
         if self.config.target_platform == Platform.IOS:
             self.library_type = LibraryType.STATIC
+        if self.config.target_platform == Platform.ANDROID:
+            self.prepend_env('PATH', self.get_env('ANDROID_NDK_TOOLCHAIN_BIN'), sep=os.pathsep)
 
 
     @modify_environment