--- a/media/webrtc/signaling/src/sipcc/cpr/include/cpr_strings.h
+++ b/media/webrtc/signaling/src/sipcc/cpr/include/cpr_strings.h
@@ -13,19 +13,23 @@
 #include "../linux/cpr_linux_strings.h"
 #elif defined SIP_OS_WINDOWS
 #include "../win32/cpr_win_strings.h"
 #elif defined SIP_OS_OSX
 #include "../darwin/cpr_darwin_strings.h"
 #endif
 
 #ifdef CPR_USE_OS_STRCASECMP
-/* Use standard library types */
+/* Use standard library types, but use the OS's name for the functions */
+#ifndef cpr_strcasecmp
 #define cpr_strcasecmp  strcasecmp
+#endif
+#ifndef cpr_strncasecmp
 #define cpr_strncasecmp strncasecmp
+#endif
 #else
 /* Prototypes */
 /**
  * cpr_strcasecmp
  *
  * @brief The CPR wrapper for strcasecmp
  *
  * The cpr_strcasecmp performs case insensitive string comparison of the "s1"

--- a/media/webrtc/signaling/src/sipcc/cpr/win32/cpr_win_strings.h
+++ b/media/webrtc/signaling/src/sipcc/cpr/win32/cpr_win_strings.h
@@ -5,9 +5,11 @@
 #ifndef CPR_WIN32_STRINGS_H_
 #define CPR_WIN32_STRINGS_H_
 
 #include <string.h>
 
 #define cpr_strcasecmp _stricmp
 #define cpr_strncasecmp _strnicmp
 
+#define CPR_USE_OS_STRCASECMP
+
 #endif /* CPR_WIN32_STRINGS_H_ */