glibc: Enable backtrace from abort on ARM

ARM stack frames for abort and raise were limited to the the actual
abort and raise call, such as:

Obtained 4 stack frames.
./test-app(print_trace+0x1c) [0x10a08]
./test-app() [0x10b3c]
/lib/libc.so.6(__default_sa_restorer+0) [0x4adae1e0]
/lib/libc.so.6(gsignal+0xa0) [0x4adacf74]

This is not terribly useful when trying to figure out what function
may have called called the abort, especially when using pthreads.

After the change the trace would now look like:

Obtained 8 stack frames.
./test-app(print_trace+0x1c) [0x10a08]
./test-app() [0x10b3c]
/lib/libc.so.6(__default_sa_restorer+0) [0x4befe1e0]
/lib/libc.so.6(gsignal+0xa0) [0x4befcf74]
/lib/libc.so.6(abort+0x134) [0x4befe358]
./test-app(dummy_function+0x50) [0x10adc]
./test-app(main+0xd4) [0x10c24]
/lib/libc.so.6(__libc_start_main+0x114) [0x4bee7a58]

(From OE-Core rev: 93bf8713d8e13c278543baea94fb8dad0cb80e49)

Signed-off-by: Yuanjie Huang <yuanjie.huang@windriver.com>
Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/glibc/glibc.inc

@@ -78,3 +78,9 @@ do_configure_prepend() {
 }
 
 GLIBC_ADDONS ?= "nptl,libidn"
+
+# Enable backtrace from abort()
+do_configure_append_arm () {
+	echo "CFLAGS-abort.c = -fasynchronous-unwind-tables" >> ${B}/configparms
+	echo "CFLAGS-raise.c = -fasynchronous-unwind-tables" >> ${B}/configparms
+}