[LyX/master] Since boost dir may not exist anymore, use the lyx-src dir for out-of-source build detection

[Kornel Benko]

commit b5a4e79736513aee6c8ef4da6eb05bee0e6ce17e
Author: Kornel Benko <kor...@lyx.org>
Date:   Wed Aug 2 18:44:32 2017 +0200

    Since boost dir may not exist anymore, use the lyx-src dir for 
out-of-source build detection
---
 src/support/Package.cpp |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/support/Package.cpp b/src/support/Package.cpp
index 4b91bba..6df4365 100644
--- a/src/support/Package.cpp
+++ b/src/support/Package.cpp
@@ -302,8 +302,8 @@ bool isBuildDir(FileName const & abs_binary, string const & 
dir_location,
         return true;
     }
     //  cmake file, no Makefile in lib
-    FileName build_boost_dir = FileName(addPath(search_dir + "/3rdparty", 
"boost"));
-    if (!fileSearch(build_boost_dir.absFileName(), 
"cmake_install.cmake").empty()) {
+    FileName build_src_dir = FileName(addPath(search_dir, "src"));
+    if (!fileSearch(build_src_dir.absFileName(), 
"cmake_install.cmake").empty()) {
         return true;
     }