Intention of this patch is to have 100% transparent byuild framework
without any hardcoded warning, optimistation or liker flags. All to be
able control those parameters from outside of the build rpm package.

Propose is for example be able inject into $CC code scaners which usually
do not undestand warning flags of code optimistation flags. 

Also it is known that in case of gccusing some combinations of -W<foo>
flags actually is able to masks/hide some warnings instead printing them
out.

--- a/configure.ac~	2021-02-23 03:14:29.000000000 +0000
+++ b/configure.ac	2021-02-24 01:06:07.269505219 +0000
@@ -27,28 +27,6 @@
 RW_PROG_CXX_WORKS
 AM_CONDITIONAL([CXX_WORKS], [test "x$rw_cv_prog_cxx_works" = "xyes"])
 
-# Detect warning flags supported by the compiler, append them to WARN_CFLAGS.
-#
-# Pass -Werror as an extra flag during the test: this is needed to make the
-# -Wunknown-warning-option diagnostic fatal with clang.
-AX_APPEND_COMPILE_FLAGS([ dnl
-		-Wall dnl
-		dnl We currently get this warning when building with Clang:
-		dnl
-		dnl /usr/include/setjmp.h:54:12: error: declaration of built-in function '__sigsetjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>. [-Werror,-Wincomplete-setjmp-declaration]
-		dnl extern int __sigsetjmp (struct __jmp_buf_tag __env[1], int __savemask) __THROWNL;
-		dnl            ^
-		-Wno-incomplete-setjmp-declaration dnl
-		-Wdiscarded-qualifiers dnl
-		-Wmissing-declarations dnl
-		-Wmissing-prototypes dnl
-		-Wmissing-parameter-type dnl
-		-Wold-style-definition dnl
-		-Wstrict-prototypes dnl
-	],
-	[WARN_CFLAGS],
-	[-Werror])
-
 # When given, add -Werror to WARN_CFLAGS.
 AC_ARG_ENABLE([Werror],
 	[AS_HELP_STRING([--enable-Werror], [Treat compiler warnings as errors.])]