Build regex.c for Solaris. Added required defines for Solaris

CMakeLists.txt

@@ -168,7 +168,7 @@ IF (ENABLE_TRACE STREQUAL "ON")
 ENDIF()
 
 # Include POSIX regex when it is required
-IF(WIN32 OR AMIGA OR ANDROID)
+IF(WIN32 OR AMIGA OR ANDROID OR CMAKE_SYSTEM_NAME MATCHES "(Solaris|SunOS)")
 	INCLUDE_DIRECTORIES(deps/regex)
 	SET(SRC_REGEX deps/regex/regex.c)
 ENDIF()
@@ -290,6 +290,10 @@ IF (MSVC)
 ELSE ()
 	SET(CMAKE_C_FLAGS "-D_GNU_SOURCE -Wall -Wextra ${CMAKE_C_FLAGS}")
 
+	IF (CMAKE_SYSTEM_NAME MATCHES "(Solaris|SunOS)")
+		SET(CMAKE_C_FLAGS "-std=c99 -D_POSIX_C_SOURCE=200112L -D__EXTENSIONS__ -D_POSIX_PTHREAD_SEMANTICS ${CMAKE_C_FLAGS}")
+	ENDIF()
+
 	IF (WIN32 AND NOT CYGWIN)
 		SET(CMAKE_C_FLAGS_DEBUG "-D_DEBUG")
 	ENDIF ()