CMake: Skip snprintf(3) tests when cross-compiling.

Same as in libpcap.

Author: infrastation

CHANGES

@@ -61,6 +61,7 @@ DayOfTheWeek, Month DD, YYYY / The Tcpdump Group
       Make illumos build warning-free.
       Makefile.in: Update the .c.o build rule (Remove hacks for old SunOS 4).
       Autoconf: fix buggy tests for ether_ntohost().
+      CMake: Skip snprintf(3) tests when cross-compiling.
     Documentation:
       man: Clarify the "any" pseudo-interface further.
 

CMakeLists.txt

@@ -491,56 +491,60 @@ else(STDLIBS_HAVE_GETSERVENT)
 endif(STDLIBS_HAVE_GETSERVENT)
 cmake_pop_check_state()
 
-#
-# Require a proof of suitable snprintf(3), same as in Autoconf.
-#
-include(CheckCSourceRuns)
-check_c_source_runs("
-#include <stdio.h>
-#include <string.h>
-#include <inttypes.h>
-#include <sys/types.h>
-
-int main()
-{
-  char buf[100];
-  uint64_t t = (uint64_t)1 << 32;
-
-  snprintf(buf, sizeof(buf), \"%zu\", sizeof(buf));
-  if (strncmp(buf, \"100\", sizeof(buf)))
-    return 1;
-
-  snprintf(buf, sizeof(buf), \"%zd\", -sizeof(buf));
-  if (strncmp(buf, \"-100\", sizeof(buf)))
-    return 2;
-
-  snprintf(buf, sizeof(buf), \"%\" PRId64, -t);
-  if (strncmp(buf, \"-4294967296\", sizeof(buf)))
-    return 3;
-
-  snprintf(buf, sizeof(buf), \"0o%\" PRIo64, t);
-  if (strncmp(buf, \"0o40000000000\", sizeof(buf)))
-    return 4;
-
-  snprintf(buf, sizeof(buf), \"0x%\" PRIx64, t);
-  if (strncmp(buf, \"0x100000000\", sizeof(buf)))
-    return 5;
-
-  snprintf(buf, sizeof(buf), \"%\" PRIu64, t);
-  if (strncmp(buf, \"4294967296\", sizeof(buf)))
-    return 6;
-
-  return 0;
-}
-
-"
-    SUITABLE_SNPRINTF
-)
-if(NOT SUITABLE_SNPRINTF)
-    message(FATAL_ERROR
+if (NOT CMAKE_CROSSCOMPILING)
+    #
+    # Require a proof of suitable snprintf(3), same as in Autoconf.
+    #
+    include(CheckCSourceRuns)
+    check_c_source_runs("
+    #include <stdio.h>
+    #include <string.h>
+    #include <inttypes.h>
+    #include <sys/types.h>
+
+    int main()
+    {
+      char buf[100];
+      uint64_t t = (uint64_t)1 << 32;
+
+      snprintf(buf, sizeof(buf), \"%zu\", sizeof(buf));
+      if (strncmp(buf, \"100\", sizeof(buf)))
+        return 1;
+
+      snprintf(buf, sizeof(buf), \"%zd\", -sizeof(buf));
+      if (strncmp(buf, \"-100\", sizeof(buf)))
+        return 2;
+
+      snprintf(buf, sizeof(buf), \"%\" PRId64, -t);
+      if (strncmp(buf, \"-4294967296\", sizeof(buf)))
+        return 3;
+
+      snprintf(buf, sizeof(buf), \"0o%\" PRIo64, t);
+      if (strncmp(buf, \"0o40000000000\", sizeof(buf)))
+        return 4;
+
+      snprintf(buf, sizeof(buf), \"0x%\" PRIx64, t);
+      if (strncmp(buf, \"0x100000000\", sizeof(buf)))
+        return 5;
+
+      snprintf(buf, sizeof(buf), \"%\" PRIu64, t);
+      if (strncmp(buf, \"4294967296\", sizeof(buf)))
+        return 6;
+
+      return 0;
+    }
+
+    "
+        SUITABLE_SNPRINTF
+    )
+    if(NOT SUITABLE_SNPRINTF)
+        message(FATAL_ERROR
 "The snprintf(3) implementation in this libc is not suitable,
 tcpdump would not work correctly even if it managed to compile."
-    )
+        )
+    endif()
+else()
+    message(STATUS "Skipped SUITABLE_SNPRINTF because cross-compiling.")
 endif()
 
 check_function_exists(getopt_long HAVE_GETOPT_LONG)