Really fix pkg-config

Without the @ONLY option, CONFIGURE_FILE would replace the variables
that are meant to be used to pkg-config at configure time.

Signed-off-by: Carlos Martín Nieto <carlos@cmartin.tk>

CMakeLists.txt

@@ -103,7 +103,7 @@ ENDIF ()
 TARGET_LINK_LIBRARIES(git2 ${CMAKE_THREAD_LIBS_INIT})
 SET_TARGET_PROPERTIES(git2 PROPERTIES VERSION ${LIBGIT2_VERSION_STRING})
 SET_TARGET_PROPERTIES(git2 PROPERTIES SOVERSION ${LIBGIT2_VERSION_MAJOR})
-CONFIGURE_FILE(libgit2.pc.in libgit2.pc)
+CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/libgit2.pc.in ${CMAKE_CURRENT_BINARY_DIR}/libgit2.pc @ONLY)
 
 # Install
 INSTALL(TARGETS git2
@@ -111,7 +111,7 @@ INSTALL(TARGETS git2
     LIBRARY DESTINATION ${INSTALL_LIB}
     ARCHIVE DESTINATION ${INSTALL_LIB}
 )
-INSTALL(FILES ${CMAKE_BINARY_DIR}/libgit2.pc DESTINATION ${INSTALL_LIB}/pkgconfig )
+INSTALL(FILES ${CMAKE_CURRENT_BINARY_DIR}/libgit2.pc DESTINATION ${INSTALL_LIB}/pkgconfig )
 INSTALL(DIRECTORY include/git2 DESTINATION ${INSTALL_INC} )
 INSTALL(FILES include/git2.h DESTINATION ${INSTALL_INC} )