From b96c62ed8b29ce6e57be667169b752d12032b8e3 Mon Sep 17 00:00:00 2001
From: sevenbill <59557584+sevenbill@users.noreply.github.com>
Date: Thu, 25 Jun 2020 14:56:26 +0200
Subject: [PATCH] Optionalized build dependency on git

Signed-off-by: Bill Morris <bill@sevendof.com>
---
 CMakeLists.txt | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6b3db82918..7813d4c010 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -47,12 +47,14 @@ message(STATUS "build type is ${CMAKE_BUILD_TYPE}")
 
 set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug;Release;RelWithDebInfo;MinSizeRel;Coverage")
 
-execute_process(
-	COMMAND git describe --always --tags
-	OUTPUT_VARIABLE git_tag
-	OUTPUT_STRIP_TRAILING_WHITESPACE
-	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-	)
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/.git)
+	execute_process(
+		COMMAND git describe --always --tags
+		OUTPUT_VARIABLE git_tag
+		OUTPUT_STRIP_TRAILING_WHITESPACE
+		WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+		)
+endif()
 
 message(STATUS "PX4 ECL: Very lightweight Estimation & Control Library ${git_tag}")