[winpr] add WINPR_ATTR_FORMAT_ARG

this macro declares the function argument (pos,arg) to be a printf
style format string and enables compiler checks for that.

channels/urbdrc/client/libusb/libusb_udevice.c

@@ -129,6 +129,8 @@ static void set_stream_id_for_buffer(struct libusb_transfer* transfer, UINT32 st
 	user_data->streamID = streamID;
 #endif
 }
+
+WINPR_ATTR_FORMAT_ARG(3, 8)
 static BOOL log_libusb_result_(wLog* log, DWORD lvl, const char* fmt, const char* fkt,
                                const char* file, size_t line, int error, ...)
 {

libfreerdp/core/aad.c

@@ -52,6 +52,7 @@ struct rdp_aad
 static BOOL get_encoded_rsa_params(wLog* wlog, rdpPrivateKey* key, char** e, char** n);
 static BOOL generate_pop_key(rdpAad* aad);
 
+WINPR_ATTR_FORMAT_ARG(2, 3)
 static SSIZE_T stream_sprintf(wStream* s, const char* fmt, ...)
 {
 	va_list ap;

libfreerdp/core/freerdp.c

@@ -1210,6 +1210,7 @@ void clearChannelError(rdpContext* context)
 	ResetEvent(context->channelErrorEvent);
 }
 
+WINPR_ATTR_FORMAT_ARG(3, 4)
 void setChannelError(rdpContext* context, UINT errorNum, const char* format, ...)
 {
 	va_list ap;

libfreerdp/core/gateway/http.c

@@ -468,6 +468,7 @@ BOOL http_request_set_transfer_encoding(HttpRequest* request, TRANSFER_ENCODING
 	return TRUE;
 }
 
+WINPR_ATTR_FORMAT_ARG(2, 3)
 static BOOL http_encode_print(wStream* s, const char* fmt, ...)
 {
 	char* str;

libfreerdp/core/gateway/tsg.c

@@ -290,6 +290,7 @@ static const char* tsg_state_to_string(TSG_STATE state)
 	}
 }
 
+WINPR_ATTR_FORMAT_ARG(3, 4)
 static BOOL tsg_print(char** buffer, size_t* len, const char* fmt, ...)
 {
 	int rc;

server/Sample/sfreerdp.c

@@ -1257,6 +1257,7 @@ static const struct
 	const char skey[6];
 } options = { "--pcap=", "--fast", "--port=", "--local-only", "--cert=", "--key=" };
 
+WINPR_ATTR_FORMAT_ARG(2, 0)
 static void print_entry(FILE* fp, const char* fmt, const char* what, size_t size)
 {
 	char buffer[32] = { 0 };

winpr/include/winpr/winpr.h

@@ -47,6 +47,12 @@
 #define WINPR_API
 #endif
 
+#if defined(__GNUC__) || defined(__clang__)
+#define WINPR_ATTR_FORMAT_ARG(pos, args) __attribute__((__format__(__printf__, pos, args)))
+#else
+#define WINPR_ATTR_FORMAT_ARG(pos, args)
+#endif
+
 #if defined(__STDC__) && defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 202311L)
 #define WINPR_DEPRECATED(obj) [[deprecated]] obj
 #define WINPR_DEPRECATED_VAR(text, obj) [[deprecated(text)]] obj

winpr/libwinpr/crt/string.c

@@ -142,6 +142,7 @@ BOOL winpr_str_append(const char* what, char* buffer, size_t size, const char* s
 	return TRUE;
 }
 
+WINPR_ATTR_FORMAT_ARG(3, 4)
 int winpr_asprintf(char** s, size_t* slen, const char* templ, ...)
 {
 	va_list ap;

winpr/libwinpr/utils/stream.c

@@ -346,6 +346,7 @@ BOOL Stream_CheckAndLogRequiredCapacityExVa(const char* tag, DWORD level, wStrea
 	return TRUE;
 }
 
+WINPR_ATTR_FORMAT_ARG(6, 0)
 BOOL Stream_CheckAndLogRequiredCapacityWLogExVa(wLog* log, DWORD level, wStream* s, size_t nmemb,
                                                 size_t size, const char* fmt, va_list args)
 {
@@ -369,6 +370,7 @@ BOOL Stream_CheckAndLogRequiredCapacityWLogExVa(wLog* log, DWORD level, wStream*
 	return TRUE;
 }
 
+WINPR_ATTR_FORMAT_ARG(6, 7)
 BOOL Stream_CheckAndLogRequiredCapacityWLogEx(wLog* log, DWORD level, wStream* s, size_t nmemb,
                                               size_t size, const char* fmt, ...)
 {
@@ -389,6 +391,7 @@ BOOL Stream_CheckAndLogRequiredCapacityWLogEx(wLog* log, DWORD level, wStream* s
 	return TRUE;
 }
 
+WINPR_ATTR_FORMAT_ARG(6, 7)
 BOOL Stream_CheckAndLogRequiredLengthEx(const char* tag, DWORD level, wStream* s, size_t nmemb,
                                         size_t size, const char* fmt, ...)
 {
@@ -439,6 +442,7 @@ BOOL Stream_CheckAndLogRequiredLengthWLogEx(wLog* log, DWORD level, wStream* s,
 	return TRUE;
 }
 
+WINPR_ATTR_FORMAT_ARG(6, 0)
 BOOL Stream_CheckAndLogRequiredLengthWLogExVa(wLog* log, DWORD level, wStream* s, size_t nmemb,
                                               size_t size, const char* fmt, va_list args)
 {