Workaround missing .pc files on FreeBSD

This fixes #2118

CMakeLists.txt

@@ -157,7 +157,11 @@ IF (WIN32 AND NOT MINGW AND NOT SHA1_TYPE STREQUAL "builtin")
 	FILE(GLOB SRC_SHA1 src/hash/hash_win32.c)
 ELSEIF (OPENSSL_FOUND AND NOT SHA1_TYPE STREQUAL "builtin")
 	ADD_DEFINITIONS(-DOPENSSL_SHA1)
+	IF (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+		SET(LIBGIT2_PC_LIBS "${LIBGIT2_PC_LIBS} -lssl")
+	ELSE()
 		SET(LIBGIT2_PC_REQUIRES "${LIBGIT2_PC_REQUIRES} openssl")
+	ENDIF ()
 ELSE()
 	FILE(GLOB SRC_SHA1 src/hash/hash_generic.c)
 ENDIF()
@@ -178,7 +182,7 @@ FIND_PACKAGE(ZLIB)
 IF (ZLIB_FOUND)
 	INCLUDE_DIRECTORIES(${ZLIB_INCLUDE_DIRS})
 	LINK_LIBRARIES(${ZLIB_LIBRARIES})
-	IF(APPLE)
+	IF(APPLE OR CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
 		SET(LIBGIT2_PC_LIBS "${LIBGIT2_PC_LIBS} -lz")
 	ELSE()
 		SET(LIBGIT2_PC_REQUIRES "${LIBGIT2_PC_REQUIRES} zlib")