build.sh: if new enough libgit2 is installed, use it

Right now this is only designed for Linux where current distros all should have
a new enough libgit2 (and our instructions tell people to install this with
system tools, so we should also use it).

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

CMakeLists.txt

@@ -22,6 +22,7 @@ option(LIBMARBLE_FROM_PKGCONFIG "use pkg-config to retrieve marble" OFF)
 
 #Library Handling
 option(FORCE_LIBSSH "force linking with libssh to workaround libgit2 bug" ON)
+option(LIBGIT2_DYNAMIC "search for libgit2.so before libgit2.a" OFF)
 
 #Options regarding disabling parts of subsurface.
 option(NO_MARBLE "disable the marble widget" OFF)

cmake/Modules/FindLIBGIT2.cmake

@@ -22,8 +22,13 @@ HINTS
     /usr/include
 )
 
+IF ( LIBGIT2_DYNAMIC )
+    SET( LIBGIT2_SO libgit2.so )
+ENDIF()
+
 FIND_LIBRARY( LIBGIT2_LIBRARIES
 NAMES
+    ${LIBGIT2_SO}
     libgit2.a
     git2
 HINTS

scripts/build.sh

@@ -3,7 +3,6 @@
 # this should be run from the src directory, the layout is supposed to
 # look like this:
 #.../src/subsurface
-#       /libgit2
 #       /marble-source
 #       /libdivecomputer
 #
@@ -73,7 +72,21 @@ export PKG_CONFIG_PATH=$INSTALL_ROOT/lib/pkgconfig:$PKG_CONFIG_PATH
 
 echo Building in $SRC, installing in $INSTALL_ROOT
 
-# build libgit2
+# set up the right file name extensions
+if [ $PLATFORM = Darwin ] ; then
+	SH_LIB_EXT=dylib
+else
+	SH_LIB_EXT=so
+
+	# check if we need to build libgit2 (and do so if necessary)
+
+	LIBGIT_ARGS=" -DLIBGIT2_DYNAMIC=ON "
+	LIBGIT=$(ldconfig -p | grep libgit2\\.so\\. | awk -F. '{ print $NF }')
+fi
+
+if [[ $PLATFORM = Darwin || "$LIBGIT" < "24" ]] ; then
+
+	LIBGIT_ARGS=" -DLIBGIT2_INCLUDE_DIR=$INSTALL_ROOT/include -DLIBGIT2_LIBRARIES=$INSTALL_ROOT/lib/libgit2.$SH_LIB_EXT "
 
 	cd $SRC
 
@@ -106,6 +119,7 @@ if [ $PLATFORM = Darwin ] ; then
 			install_name_tool -id "$INSTALL_ROOT/lib/$NAME" "$INSTALL_ROOT/lib/$NAME"
 		fi
 	fi
+fi
 
 cd $SRC
 
@@ -227,12 +241,6 @@ fi
 
 # finally, build Subsurface
 
-if [ $PLATFORM = Darwin ] ; then
-	SH_LIB_EXT=dylib
-else
-	SH_LIB_EXT=so
-fi
-
 cd $SRC/subsurface
 for (( i=0 ; i < ${#BUILDS[@]} ; i++ )) ; do
 	SUBSURFACE_EXECUTABLE=${BUILDS[$i]}
@@ -250,8 +258,7 @@ for (( i=0 ; i < ${#BUILDS[@]} ; i++ )) ; do
 	export CMAKE_PREFIX_PATH="$INSTALL_ROOT/lib/cmake;${CMAKE_PREFIX_PATH}"
 	cmake -DCMAKE_BUILD_TYPE=Debug .. \
 		-DSUBSURFACE_TARGET_EXECUTABLE=$SUBSURFACE_EXECUTABLE \
-		-DLIBGIT2_INCLUDE_DIR=$INSTALL_ROOT/include \
+		${LIBGIT_ARGS} \
-		-DLIBGIT2_LIBRARIES=$INSTALL_ROOT/lib/libgit2.$SH_LIB_EXT \
 		-DLIBDIVECOMPUTER_INCLUDE_DIR=$INSTALL_ROOT/include \
 		-DLIBDIVECOMPUTER_LIBRARIES=$INSTALL_ROOT/lib/libdivecomputer.a \
 		-DMARBLE_INCLUDE_DIR=$INSTALL_ROOT/include \