From 44c80e5d8bf5d86dc15761f504e7fe0114abd1c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Janiszewski?=
 <janisozaur@users.noreply.github.com>
Date: Mon, 29 Oct 2018 23:39:33 +0100
Subject: [PATCH] Handle missing git info when building

---
 .../cmake-modules/GetGitRevisionDescription.cmake.in      | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/externals/cmake-modules/GetGitRevisionDescription.cmake.in b/externals/cmake-modules/GetGitRevisionDescription.cmake.in
index 888ce13aa..0d7eb3c26 100644
--- a/externals/cmake-modules/GetGitRevisionDescription.cmake.in
+++ b/externals/cmake-modules/GetGitRevisionDescription.cmake.in
@@ -33,6 +33,10 @@ else()
 endif()
 
 if(NOT HEAD_HASH)
-	file(READ "@GIT_DATA@/head-ref" HEAD_HASH LIMIT 1024)
-	string(STRIP "${HEAD_HASH}" HEAD_HASH)
+	if(EXISTS "@GIT_DATA@/head-ref")
+		file(READ "@GIT_DATA@/head-ref" HEAD_HASH LIMIT 1024)
+		string(STRIP "${HEAD_HASH}" HEAD_HASH)
+	else()
+		set(HEAD_HASH "Unknown")
+	endif()
 endif()