[Mesa-dev] [PATCH mesa] travis: avoid using unset llvm-config

[Eric Engestrom]

Fixes the following errors:
  usage: which [-as] program ...
  /Users/travis/.travis/job_stages: line 110: --version: command not found

... caused by the use of an undefined $LLVM_CONFIG

Signed-off-by: Eric Engestrom <eric.engestrom at intel.com>
---
 .travis.yml | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index b70df99d67efde5e35c8..7279f3ad9cf1dab9e3bf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -823,12 +823,16 @@ script:
 
   - |
     if test "x$BUILD" = xmeson; then
-      # We need to control the version of llvm-config we're using, so we'll
-      # generate a native file to do so. This requires meson >=0.49
-      #
-      echo -e "[binaries]\nllvm-config = '`which $LLVM_CONFIG`'" > native.file
+      if test -n "$LLVM_CONFIG"; then
+        # We need to control the version of llvm-config we're using, so we'll
+        # generate a native file to do so. This requires meson >=0.49
+        #
+        echo -e "[binaries]\nllvm-config = '`which $LLVM_CONFIG`'" > native.file
 
-      $LLVM_CONFIG --version
+        $LLVM_CONFIG --version
+      else
+        : > native.file
+      fi
 
       export CFLAGS="$CFLAGS -isystem`pwd`"
       meson _build \
-- 
Cheers,
  Eric