set LIBRARY_PATH for macos

Author: mattip

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Windows build
+name: Win
 
 on:
   push:

.github/workflows/multibuild.yml

@@ -1,4 +1,4 @@
-name: Linux,macOS build
+name: multibuild
 
 on:
   push:
@@ -78,6 +78,7 @@ jobs:
         if [ "macos-11" == "${{ matrix.os }}" ]; then
           echo "TRAVIS_OS_NAME=osx" >> $GITHUB_ENV; else echo "TRAVIS_OS_NAME=${{ matrix.os }}" >> $GITHUB_ENV;
           echo "LDFLAGS=-L/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib" >> $GITHUB_ENV;
+          echo "LIBRARY_PATH=-L/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib" >> $GITHUB_ENV;
         fi
         echo "DOCKER_TEST_IMAGE=$(echo multibuild/xenial_${{ matrix.PLAT}})" >> $GITHUB_ENV;
     - name: Print some Environment variable