gcc: add Xcode 15 patch

Author: fxcoudert

gcc/gcc-xcode15-warnings.diff

@@ -0,0 +1,25 @@
+diff --git a/gcc/config/aarch64/darwin.h b/gcc/config/aarch64/darwin.h
+index 5609c569dc1..9fcbfa3d777 100644
+--- a/gcc/config/aarch64/darwin.h
++++ b/gcc/config/aarch64/darwin.h
+@@ -65,10 +65,6 @@ along with GCC; see the file COPYING3.  If not see
+ #define DARWIN_NOPIE_SPEC \
+ " %<no-pie %<fno-pie %<fno-PIE "
+ 
+-/* Hack alert - we want the exported cas etc.  */
+-#undef LIB_SPEC
+-#define LIB_SPEC "%{!static:-lSystem} -lgcc"
+-
+ /* Force the default endianness and ABI flags onto the command line
+    in order to make the other specs easier to write.  Match clang in
+    silently ignoring mdynamic-no-pic */
+diff --git a/libgfortran/libgfortran.spec.in b/libgfortran/libgfortran.spec.in
+index 367d485c230..058ee5775bf 100644
+--- a/libgfortran/libgfortran.spec.in
++++ b/libgfortran/libgfortran.spec.in
+@@ -5,4 +5,4 @@
+ #
+ 
+ %rename lib liborig
+-*lib: @LIBQUADSPEC@ @LIBM@ %(libgcc) %(liborig)
++*lib: @LIBQUADSPEC@ @LIBM@ %(liborig)