Try to catch missing std includes on travis

By defining LWIP_PLATFORM_ASSERT to a function, we can prevent arch.h
from including stdio.h and stdlib.h

Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>

src/apps/http/makefsdata/makefsdata.c

@@ -81,6 +81,10 @@ int deflate_level = 10; /* default compression level, can be changed via command
 #define NEWLINE     "\r\n"
 #define NEWLINE_LEN 2
 
+/* Define this here since we don't include any external C files and ports might override it */
+#define LWIP_PLATFORM_ASSERT(x) do {printf("Assertion \"%s\" failed at line %d in %s\n", \
+                                     x, __LINE__, __FILE__); fflush(NULL); abort();} while(0)
+
 /* define this to get the header variables we use to build HTTP headers */
 #define LWIP_HTTPD_DYNAMIC_HEADERS 1
 #define LWIP_HTTPD_SSI             1