Update git_hash.sh

config/git_hash.sh

 #!/bin/bash
-echo "#define GIT_HASH" \"`git describe --always --dirty=+ --tags --long --abbrev=16`\" > $1
+cd $1; echo "#define GIT_HASH" \"`git describe --always --dirty=+ --tags --long --abbrev=16`\" > $2

tracelib/CMakeLists.txt

 add_custom_command (
   OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/git_hash.h
-  COMMAND ${SHELL_EXECUTABLE} ${CMAKE_SOURCE_DIR}/config/git_hash.sh ${CMAKE_CURRENT_BINARY_DIR}/git_hash.h
+  COMMAND ${SHELL_EXECUTABLE} ${CMAKE_SOURCE_DIR}/config/git_hash.sh ${CMAKE_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}/git_hash.h
   )
 
 add_custom_command (