Add --skipcommitprinting flag in cibuild.sh

For cases where git isn't on the path, git is an older version that
doesn't support all the flags we need or the repository we are building
is not actually a git repository.

cibuild.sh

@@ -7,18 +7,19 @@ usage()
     echo "usage: cibuild.sh [options]"
     echo ""
     echo "Options"
-    echo "  --debug         Build Debug (default)"
-    echo "  --release       Build Release"
-    echo "  --skiptests     Do not run tests"
-    echo "  --skipcrossgen  Do not crossgen the bootstrapped compiler"
+    echo "  --debug               Build Debug (default)"
+    echo "  --release             Build Release"
+    echo "  --skiptests           Do not run tests"
+    echo "  --skipcrossgen        Do not crossgen the bootstrapped compiler"
+    echo "  --skipcommitprinting  Do not print commit information"
     echo "  --nocache       Force download of toolsets"
-
 }
 
 BUILD_CONFIGURATION=Debug
 USE_CACHE=true
 SKIP_TESTS=false
 SKIP_CROSSGEN=false
+SKIP_COMMIT_PRINTING=false
 
 MAKE="make"
 if [[ $OSTYPE == *[Bb][Ss][Dd]* ]]; then
@@ -62,6 +63,10 @@ do
         SKIP_CROSSGEN=true
         shift 1
         ;;
+        --skipcommitprinting)
+        SKIP_COMMIT_PRINTING=true
+        shift 1
+        ;;
         *)
         usage 
         exit 1
@@ -81,8 +86,10 @@ if [ "$USE_CACHE" == "false" ]; then
     $MAKE clean_toolset
 fi
 
-echo Building this commit:
-git show --no-patch --pretty=raw HEAD
+if [ "$SKIP_COMMIT_PRINTING" == "false" ]; then
+    echo Building this commit:
+    git show --no-patch --pretty=raw HEAD
+fi
 
 echo Building Bootstrap
 $MAKE bootstrap $MAKE_ARGS