Remove -fomit-frame-pointer flag

This seems to give only a very small speedup (1-3% in DominoEX/Thor and
Olivia) and makes debugging impossible on x86.

m4/debug.m4

@@ -83,7 +83,7 @@ AC_DEFUN([AC_FLDIGI_DEBUG], [
           gflag="-g"
       fi
       AC_MSG_RESULT([$gflag])
-      DEBUG_CFLAGS="-O0 -fno-inline-functions -fno-omit-frame-pointer $gflag -Wall"
+      DEBUG_CFLAGS="-O0 -fno-inline-functions $gflag -Wall"
 
       AC_FLDIGI_RDYNAMIC
       if test "x$ac_cv_rdynamic" = "xyes"; then

m4/opt.m4

@@ -7,7 +7,7 @@ AC_DEFUN([AC_FLDIGI_OPT], [
                   *)                         AC_MSG_ERROR([bad value ${enableval} for --enable-optimizations]) ;;
                  esac],
                  [ac_cv_opt=none])
-  OPT_CFLAGS="-O2 -ffast-math -finline-functions -fomit-frame-pointer"
+  OPT_CFLAGS="-O2 -ffast-math -finline-functions"
   case "$ac_cv_opt" in
       sse)
           OPT_CFLAGS="$OPT_CFLAGS -msse -mfpmath=sse"