+# Check for availability of various gcc command-line options.
+#
+###############################################################################
+
+AC_DEFUN(AC_CHECK_GCC_ARG,
+ [if test -n "$GCC"; then
+ AC_CACHE_CHECK([whether gcc accepts [$2]],
+ ac_cv_gcc_accepts_[$1],
+ [rm -rf conftest.$ac_ext
+ touch conftest.$ac_ext
+ if ( ( gcc -c [$2] conftest.$ac_ext -o/dev/null >/dev/null ) 2>&1 | \
+ grep unrecognized >/dev/null ); then
+ ac_cv_gcc_accepts_[$1]=no
+ else
+ ac_cv_gcc_accepts_[$1]=yes
+ CC="$CC [$2]"
+ fi])
+ ac_gcc_accepts_[$1]="$ac_cv_gcc_accepts_[$1]"
+ fi
+])
+
+AC_DEFUN(AC_NO_LONG_STRING_WARNINGS,
+ [AC_CHECK_GCC_ARG(no_overlength, -Wno-overlength-strings)])
+
+AC_DEFUN(AC_NO_MISPLACED_DECLARATIONS,
+ [AC_CHECK_GCC_ARG(no_decl_after, -Wdeclaration-after-statement)])
+
+# Need to disable Objective C extensions in ANSI C on MacOS X to work
+# around an Apple-specific gcc bug.
+#
+AC_DEFUN(AC_NO_OBJECTIVE_C,
+ [AC_CHECK_GCC_ARG(no_cpp_precomp, -no-cpp-precomp)])
+
+###############################################################################
+#
+# Function to figure out how to disable // comments in ANSI C code.