[LyX/master] Get full version of gcc

[Jean-Marc Lasgouttes]

commit 44bbd0b0ef8450f4d88dfb8c3345118f2fd14dfc
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Wed Jun 12 20:17:55 2019 +0200

    Get full version of gcc
    
    Recent gcc versions return a short version with -dumpversion, e.g. 9.
    
    In this case, use -dumpfullversion, which gives something like 9.1.0.
    
    This makes the gcc 9 detection work properly.
---
 config/lyxinclude.m4 |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/config/lyxinclude.m4 b/config/lyxinclude.m4
index f77e348..9fe42e8 100644
--- a/config/lyxinclude.m4
+++ b/config/lyxinclude.m4
@@ -381,6 +381,10 @@ if test x$GXX = xyes; then
   if test x$CLANG = xno; then
     dnl Useful for global version info
     gxx_version=`${CXX} -dumpversion`
+    case $gxx_version in
+       *.*) ;;
+       *) gxx_version=`${CXX} -dumpfullversion` ;;
+    esac
     CXX_VERSION="($gxx_version)"
   else
     gxx_version=clang-$clang_version