Revert "os: Prevent backtrace from being stopped in noreturn functions."

This reverts commit 579715f830.

The patch is not needed anymore. I haven't encountered backtrace
problems with GCC 4.3.3. Even if the problems still persisted, this
commit should be removed and instead the definition of _X_NORETURN
should be modified to be empty if GCC/ARM is used. However, currently
it seems that ARM backtraces are OK even if _X_NORETURN is used and
-mapcs-frame is not defined in CFLAGS.

Signed-off-by: Rami Ylimäki <rami.ylimaki@vincit.fi>
Reviewed-by: Jamey Sharp <jamey@minilop.net>

configure.ac

@@ -312,19 +312,6 @@ AC_CHECK_HEADER([execinfo.h],[
     ])]
 )
 
-dnl ARM needs additional compiler flags for proper backtraces if GCC is
-dnl used. Compile a dummy program with the -mapcs-frame option. If it
-dnl succeeds, we know that we are building for ARM with GCC.
-old_CFLAGS="$CFLAGS"
-CFLAGS="-mapcs-frame"
-AC_COMPILE_IFELSE(
-        AC_LANG_PROGRAM([[ ]]),
-        ARM_BACKTRACE_CFLAGS="$CFLAGS",
-        ARM_BACKTRACE_CFLAGS=""
-)
-CFLAGS="$old_CFLAGS"
-AC_SUBST(ARM_BACKTRACE_CFLAGS)
-
 dnl ---------------------------------------------------------------------------
 dnl Bus options and CPU capabilities.  Replaces logic in
 dnl hw/xfree86/os-support/bus/Makefile.am, among others.

os/Makefile.am

@@ -1,19 +1,11 @@
-noinst_LTLIBRARIES = libos.la liblog.la
+noinst_LTLIBRARIES = libos.la
 
 AM_CFLAGS = $(DIX_CFLAGS) $(SHA1_CFLAGS)
 
 SECURERPC_SRCS = rpcauth.c
 XDMCP_SRCS = xdmcp.c
 STRLCAT_SRCS = strlcat.c strlcpy.c
-
-# Build a convenience library liblog.la that will be added into
-# libos.la. The split is done so that log.c can be built with
-# different compiler options.
-liblog_la_SOURCES = log.c
-# Add flags needed for proper backtraces of functions marked with GCC
-# __attribute__((noreturn)). Currently those flags are needed for
-# FatalError and AbortServer in log.c.
-liblog_la_CFLAGS = $(AM_CFLAGS) $(ARM_BACKTRACE_CFLAGS)
+XORG_SRCS = log.c
 
 libos_la_SOURCES = 	\
 	WaitFor.c	\
@@ -32,8 +24,9 @@ libos_la_SOURCES = 	\
 	xdmauth.c	\
 	xsha1.c		\
 	xstrans.c	\
-	xprintf.c
-libos_la_LIBADD = @SHA1_LIBS@ $(DLOPEN_LIBS) liblog.la
+	xprintf.c	\
+	$(XORG_SRCS)
+libos_la_LIBADD = @SHA1_LIBS@ $(DLOPEN_LIBS)
 
 if SECURE_RPC
 libos_la_SOURCES += $(SECURERPC_SRCS)