Fix compiler warnings in cmake tests

This will not be visible to users, and it won't make it
possible to run cmake with -Werror since lots of internal tests
do not work, but since I fixed a couple of them we might
as well put it in gerrit.

Known remaining issues:
- HAVE_LIBM

Refs #1750.

Change-Id: I734f83f229108e50e2914d455f4032137f924773

Author: Erik Lindahl

CMakeLists.txt

@@ -336,21 +336,21 @@ check_include_files(regex.h      HAVE_POSIX_REGEX)
 # TODO: It could be nice to inform the user if no regex support is found,
 # as selections won't be fully functional.
 
-include(CheckFunctionExists)
-check_function_exists(posix_memalign    HAVE_POSIX_MEMALIGN)
-check_function_exists(memalign          HAVE_MEMALIGN)
-check_function_exists(_aligned_malloc   HAVE__ALIGNED_MALLOC)
-check_function_exists(gettimeofday      HAVE_GETTIMEOFDAY)
-check_function_exists(fsync             HAVE_FSYNC)
-check_function_exists(_fileno           HAVE__FILENO)
-check_function_exists(fileno            HAVE_FILENO)
-check_function_exists(_commit           HAVE__COMMIT)
-check_function_exists(sigaction         HAVE_SIGACTION)
-check_function_exists(sysconf           HAVE_SYSCONF)
-check_function_exists(rsqrt             HAVE_RSQRT)
-check_function_exists(rsqrtf            HAVE_RSQRTF)
-check_function_exists(sqrtf             HAVE_SQRTF)
-check_function_exists(nice              HAVE_NICE)
+include(CheckCXXSymbolExists)
+check_cxx_symbol_exists(posix_memalign    stdlib.h     HAVE_POSIX_MEMALIGN)
+check_cxx_symbol_exists(memalign          stdlib.h     HAVE_MEMALIGN)
+check_cxx_symbol_exists(_aligned_malloc   stdlib.h     HAVE__ALIGNED_MALLOC)
+check_cxx_symbol_exists(gettimeofday      sys/time.h   HAVE_GETTIMEOFDAY)
+check_cxx_symbol_exists(sysconf           unistd.h     HAVE_SYSCONF)
+check_cxx_symbol_exists(nice              unistd.h     HAVE_NICE)
+check_cxx_symbol_exists(fsync             unistd.h     HAVE_FSYNC)
+check_cxx_symbol_exists(_fileno           stdio.h      HAVE__FILENO)
+check_cxx_symbol_exists(fileno            stdio.h      HAVE_FILENO)
+check_cxx_symbol_exists(_commit           io.h         HAVE__COMMIT)
+check_cxx_symbol_exists(sigaction         signal.h     HAVE_SIGACTION)
+check_cxx_symbol_exists(rsqrt             math.h       HAVE_RSQRT)
+check_cxx_symbol_exists(rsqrtf            math.h       HAVE_RSQRTF)
+check_cxx_symbol_exists(sqrtf             math.h       HAVE_SQRTF)
 
 include(CheckLibraryExists)
 check_library_exists(m sqrt "" HAVE_LIBM)

cmake/TestAVXMaskload.c

@@ -13,5 +13,6 @@ int main()
 #else
     a = _mm256_maskload_pd(d,mask);
 #endif
+    return 0;
 }
 

cmake/TestFileOffsetBits.c

@@ -1,10 +1,10 @@
 #include <sys/types.h>
 
-int main(int argc, char **argv)
+int main()
 {
   /* Cause a compile-time error if off_t is smaller than 64 bits */
 #define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
   int off_t_is_large[ (LARGE_OFF_T % 2147483629 == 721 && LARGE_OFF_T % 2147483647 == 1) ? 1 : -1 ];  
-  return 0;
+  return off_t_is_large[0];
 }
 

cmake/TestFloatFormat.cpp

@@ -48,11 +48,12 @@ volatile const double abc [10] = {
     (double) -5.22995989424860458374e+10, (double) 0.0,
 };
 
+/* Check that a double is 8 bytes - compilation dies if it isnt */
+extern char xyz [sizeof(double) == 8 ? 1 : -1];
+
 int
 main()
 {
-    /* Check that a double is 8 bytes - compilation dies if it isnt */
-    extern char xyz [sizeof(double) == 8 ? 1 : -1];
     int         i;
     double      d;
 

cmake/TestLargeFiles.c.cmakein

@@ -19,6 +19,6 @@ int main(int argc, char **argv)
 
   fseeko( fp, offset, SEEK_CUR );
   fclose(fp);
-  return 0;
+  return off_t_is_large[0] || argc;
 }
 

cmake/TestPipes.c

@@ -6,5 +6,5 @@ main()
   FILE *fp;
 
   fp = popen("/tmp/xyz","r");
-  return 0;
+  return (fp==NULL);
 }

cmake/TestXDR.c

@@ -4,7 +4,9 @@
 int
 main()
 {
-  XDR *xd; 
+  /* This should only compile, not run, so set xd to NULL */
+  XDR *xd = NULL;
   float f; 
   xdr_float(xd,&f);
+  return 0;
 }    

cmake/gmxTestIsfinite.cmake

@@ -1,7 +1,7 @@
 #
 # This file is part of the GROMACS molecular simulation package.
 #
-# Copyright (c) 2012,2014, by the GROMACS development team, led by
+# Copyright (c) 2012,2014,2015, by the GROMACS development team, led by
 # Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
 # and including many others, as listed in the AUTHORS file in the
 # top-level source directory and at http://www.gromacs.org.
@@ -61,6 +61,7 @@ MACRO(gmx_test_isfinite VARIABLE)
 int main(void) {
   float f;
   isfinite(f);
+  return 0;
 }" isfinite_compile_ok)
 
     if(isfinite_compile_ok)

cmake/gmxTestdlopen.cmake

@@ -1,7 +1,7 @@
 #
 # This file is part of the GROMACS molecular simulation package.
 #
-# Copyright (c) 2012, by the GROMACS development team, led by
+# Copyright (c) 2012,2015, by the GROMACS development team, led by
 # Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
 # and including many others, as listed in the AUTHORS file in the
 # top-level source directory and at http://www.gromacs.org.
@@ -49,6 +49,7 @@ MACRO(GMX_TEST_DLOPEN VARIABLE)
       "#include <dlfcn.h>
 int main(void) {
   dlopen(0,0);
+  return 0;
 }" ${VARIABLE})
 
     IF(${VARIABLE})