diff --git a/configure.ac b/configure.ac index 1276dfaacd527..1722d0abd85dc 100644 --- a/configure.ac +++ b/configure.ac @@ -88,11 +88,14 @@ esac AC_DEFUN([SECP_TRY_APPEND_DEFAULT_CFLAGS], [ # GCC and compatible (incl. clang) if test "x$GCC" = "xyes"; then - # Try to append -Werror=unknown-warning-option to CFLAGS temporarily. Otherwise clang will - # not error out if it gets unknown warning flags and the checks here will always succeed - # no matter if clang knows the flag or not. + # Try to append -Werror to CFLAGS temporarily. Otherwise checks for some unsupported + # flags will succeed. + # Note that failure to append -Werror does not necessarily mean that -Werror is not + # supported. The compiler may already be warning about something unrelated, for example + # about some path issue. If that is the case, -Werror cannot be used because all + # of those warnings would be turned into errors. SECP_TRY_APPEND_DEFAULT_CFLAGS_saved_CFLAGS="$CFLAGS" - SECP_TRY_APPEND_CFLAGS([-Werror=unknown-warning-option], CFLAGS) + SECP_TRY_APPEND_CFLAGS([-Werror], CFLAGS) SECP_TRY_APPEND_CFLAGS([-std=c89 -pedantic -Wno-long-long -Wnested-externs -Wshadow -Wstrict-prototypes -Wundef], $1) # GCC >= 3.0, -Wlong-long is implied by -pedantic. SECP_TRY_APPEND_CFLAGS([-Wno-overlength-strings], $1) # GCC >= 4.2, -Woverlength-strings is implied by -pedantic.