A slightly modified g++/clang++ check.

diff --git a/configure.ac b/configure.ac
index d665498d2e9532289ae3a049b3abc2b0a7e457bc..f6ca5e667965510d5e417a0fcbbd490019840a05 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -204,30 +204,28 @@ if test x"$enable_simd" != x"no"; then
     # For x86-64 SIMD, g++ >=5 or clang++ >=7 is required
     if test x"$build_cpu" = x"x86_64"; then
        CXX_OK=
-       if test x"$CXX" != x""; then
-           CXX_VERSION=`$CXX --version 2>/dev/null | head -n 1`
-           case "$CXX_VERSION" in
-           g++*)
-               CXX_VERSION=`$CXX -dumpversion | sed 's/\..*//g'`
-               if test "$CXX_VERSION" -ge "5"; then
-                   CXX_OK=yes
-               fi
-               ;;
-           *clang*)
-               # $CXX -dumpversion would have been ideal, but is broken on older clang
-               CXX_VERSION=`echo "$CXX_VERSION" | sed 's/.*version //g' | sed 's/\..*//g'`
-               if test "$CXX_VERSION" -ge "7"; then
-                   CXX_OK=yes
-               fi
-               ;;
-           *)
-               CXX_VERSION='Unknown'
-               ;;
-           esac
-       else
+       case "$CXX" in
+       g++|*-g++)
+           CXX_VERSION=`$CXX -dumpversion | sed 's/\..*//'`
+           if test "$CXX_VERSION" -ge "5"; then
+               CXX_OK=yes
+           fi
+           ;;
+       *clang*)
+           # -dumpversion is broken on older clang versions, so we need a fallback.
+           CXX_VERSION=`$CXX -dumpversion 2>/dev/null | sed 's/\..*//'`
+           if test x"$CXX_VERSION" = x; then
+               CXX_VERSION=`$CXX --version | head -n 1 | sed 's/.*version //' | sed 's/\..*//'`
+           fi
+           if test "$CXX_VERSION" -ge "7"; then
+               CXX_OK=yes
+           fi
+           ;;
+       *)
            CXX='No c++'
            CXX_VERSION='Unknown'
-       fi
+           ;;
+       esac
        if test x"$CXX_OK" = x"yes"; then
            # AC_MSG_RESULT() is called below.
            SIMD="$SIMD x86_64"