mkmf.log

"xcrun clang -o conftest -I/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/ruby-2.3.0/universal-darwin17 -I/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/ruby-2.3.0/ruby/backward -I/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/ruby-2.3.0 -I. -I/usr/local/Cellar/postgresql/10.1/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -g -Os -pipe -DHAVE_GCC_ATOMIC_BUILTINS -iwithsysroot /usr/local/libressl/include conftest.c  -L. -L/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib -L/usr/local/lib -L.             -L /BuildRoot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.Internal.sdk/usr/local/libressl/lib -L/BuildRoot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.Internal.sdk/usr/local/lib -Wl,-rpath,/usr/local/lib   -arch x86_64 -arch i386   -lruby.2.3.0 -llibpq  -lpthread -ldl -lobjc "
conftest.c:15:13: error: conflicting types for 'PQconnectdb'
extern void PQconnectdb();
            ^
/usr/local/Cellar/postgresql/10.1/include/libpq-fe.h:261:16: note: previous declaration is here
extern PGconn *PQconnectdb(const char *conninfo);
               ^
conftest.c:16:27: error: too few arguments to function call, single argument 'conninfo' was not specified
int t(void) { PQconnectdb(); return 0; }
              ~~~~~~~~~~~ ^
/usr/local/Cellar/postgresql/10.1/include/libpq-fe.h:261:1: note: 'PQconnectdb' declared here
extern PGconn *PQconnectdb(const char *conninfo);
^
2 errors generated.
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: #include <libpq-fe.h>
 4: 
 5: /*top*/
 6: extern int t(void);
 7: int main(int argc, char **argv)
 8: {
 9:   if (argc > 1000000) {
10:     printf("%p", &t);
11:   }
12: 
13:   return 0;
14: }
15: extern void PQconnectdb();
16: int t(void) { PQconnectdb(); return 0; }
/* end */