cmake: add missing requires to the .pc file

src/CMakeLists.txt

@@ -140,12 +140,14 @@ ELSEIF(REGEX_BACKEND STREQUAL "pcre2")
 
 	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${PCRE2_INCLUDE_DIRS})
 	LIST(APPEND LIBGIT2_LIBS ${PCRE2_LIBRARIES})
+	LIST(APPEND LIBGIT2_PC_REQUIRES "libpcre2")
 ELSEIF(REGEX_BACKEND STREQUAL "pcre")
 	ADD_FEATURE_INFO(regex ON "using system PCRE")
 	SET(GIT_REGEX_PCRE 1)
 
 	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${PCRE_INCLUDE_DIRS})
 	LIST(APPEND LIBGIT2_LIBS ${PCRE_LIBRARIES})
+	LIST(APPEND LIBGIT2_PC_REQUIRES "libpcre")
 ELSEIF(REGEX_BACKEND STREQUAL "regcomp")
 	ADD_FEATURE_INFO(regex ON "using system regcomp")
 	SET(GIT_REGEX_REGCOMP 1)