Follow-up Comment #1, sr #110400 (project autoconf): The error happens in the expansion of the macro _AC_UNDECLARED_WARNING:
# For AC_CHECK_DECL to react to warnings, the compiler must be silent on # valid AC_CHECK_DECL input. No library function is consistently available # on freestanding implementations, so test against a dummy declaration. # Include always-available headers on the off chance that they somehow # elicit warnings. cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ #include <float.h> #include <limits.h> #include <stdarg.h> #include <stddef.h> extern void ac_decl (int, char *); int main (void) { #ifdef __cplusplus (void) ac_decl ((int) 0, (char *) 0); (void) ac_decl; #else (void) ac_decl; #endif ; return 0; } _ACEOF if ac_fn_c_try_compile "$LINENO" then : if test -s conftest.err then : { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5 printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;} as_fn_error $? "cannot detect from compiler exit status or warnings See \`config.log' for more details" "$LINENO" 5; } The problem here is the semicolon before 'return 0', which comes from the AC_LANG_PROGRAM macro. It triggers a clang warning. And since all or most test programs used by Autoconf are pieced together using AC_LANG_PROGRAM, the presence of warnings cannot be used to detect anything about the test program. _______________________________________________________ Reply to this item at: <https://savannah.gnu.org/support/?110400> _______________________________________________ Message sent via Savannah https://savannah.gnu.org/