Bugfix: Set Github env fallbacks for detecting non-ci environment

Author: hhvrc

scripts/embed_env_vars.py

@@ -18,10 +18,11 @@
 # If we are running in CI and either building the master branch,
 # or building a PR that will merge into the master branch, THEN
 # we will build in RELEASE mode.
-is_ci = sysenv.get_bool('CI')
-is_branch_master = sysenv.get_string('GITHUB_REF_NAME') == 'master'
+is_ci = sysenv.get_bool('CI', False)
+is_branch_master = sysenv.get_string('GITHUB_REF_NAME', '') == 'master'
 is_pr_into_master = (
-    sysenv.get_string('GITHUB_BASE_REF') == 'master' and sysenv.get_string('GITHUB_EVENT_NAME', '') == 'pull_request'
+    sysenv.get_string('GITHUB_BASE_REF', '') == 'master'
+    and sysenv.get_string('GITHUB_EVENT_NAME', '') == 'pull_request'
 )
 is_release_build = is_ci and (is_branch_master or is_pr_into_master)