example: do not pass empty environment variables to example setup

Signed-off-by: Gordon Hecker <gh@emlix.com>

diff --git a/example/Makefile b/example/Makefile
index 470ccc098d44fbcced7cfd646f6548c70c3d11cb..6533ba1899ec9321d7b3179cf4baa66946cff8c5 100644 (file)
--- a/example/Makefile
+++ b/example/Makefile
@@ -43,6 +43,16 @@ RELEASESDIR = $(LOCALSTATEDIR)/releases
 PROJECTSDIR = $(LOCALSTATEDIR)/projects
 UPSTREAMDIR = $(LOCALSTATEDIR)/upstream
 
+ifneq ($(E2_LOCAL_BRANCH),)
+  E2_LOCAL_BRANCH_ENV = E2_LOCAL_BRANCH=$(E2_LOCAL_BRANCH)
+endif
+ifneq ($(E2_LOCAL_TAG),)
+  E2_LOCAL_TAG_ENV = E2_LOCAL_TAG=$(E2_LOCAL_TAG)
+endif
+ifneq ($(E2_CONFIG),)
+  E2_CONFIG_ENV = E2_CONFIG=$(E2_CONFIG)
+endif
+
 default: example
 
 clean:
@@ -70,11 +80,11 @@ install_example: fetch
        # process to the local build inside e2-fetch-project.
        env -i \
                PATH=$(PATH) \
-               E2_CONFIG=$(E2_CONFIG) \
+               $(E2_CONFIG_ENV) \
                HOME=$(HOME) \
                USER=$(USER) \
-               E2_LOCAL_BRANCH=$(E2_LOCAL_BRANCH) \
-               E2_LOCAL_TAG=$(E2_LOCAL_TAG) \
+               $(E2_LOCAL_BRANCH_ENV) \
+               $(E2_LOCAL_TAG_ENV) \
                ./setup_example.sh
 
 uninstall_example: