build-sys: fix conftest.c to work on arm

All tests for compiler support were failing with:

/usr/bin/ld: /tmp/ccwnVc2A.o: relocation R_ARM_MOVW_ABS_NC against `a' can not be used when making a shared object; recompile with -fPIC

diff --git a/m4/attributes.m4 b/m4/attributes.m4
index aa53ef238027826b3f8d2d24fea27cc18c6aee71..7bd5ad8ef64e6f9d07961a6548fb8e48a9e39ff7 100644 (file)
--- a/m4/attributes.m4
+++ b/m4/attributes.m4
@@ -42,7 +42,7 @@ AC_DEFUN([CC_CHECK_FLAG_APPEND], [
                  AS_TR_SH([cc_cv_$2_$3]),
           [eval "AS_TR_SH([cc_save_$2])='${$2}'"
            eval "AS_TR_SH([$2])='-Werror $3'"
-           AC_LINK_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
+           AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; } ])],
                           [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
                           [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
            eval "AS_TR_SH([$2])='$cc_save_$2'"])