Compile failure when using autoconf 2.71

[ryandesign]

Hi, moon-buggy does not compile (on macOS 10.15.7 or macOS 12.3; OS version probably irrelevant) when the configure script was generated by autoconf 2.71:

In file included from mode.c:9:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/stdlib.h:66:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/wait.h:109:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/signal.h:155:
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/_types/_size_t.h:31:32: error: cannot combine with previous 'type-name' declaration specifier
typedef __darwin_size_t        size_t;
                               ^
./config.h:124:25: note: expanded from macro 'size_t'
#define size_t unsigned int
                        ^

This happened because the configure script could not find size_t:

configure:5273: /usr/bin/clang -c -pipe -Os -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk -arch arm64 -I/opt/local/include -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk conftest.c >&5
In file included from conftest.c:35:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/stdlib.h:66:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/wait.h:109:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/signal.h:156:
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/_types/_uid_t.h:31:31: error: cannot combine with previous 'type-name' declaration specifier
typedef __darwin_uid_t        uid_t;
                              ^
conftest.c:27:15: note: expanded from macro 'uid_t'
#define uid_t int
              ^
In file included from conftest.c:50:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/types.h:109:
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/_types/_gid_t.h:31:25: error: cannot combine with previous 'type-name' declaration specifier
typedef __darwin_gid_t  gid_t;
                        ^
conftest.c:28:15: note: expanded from macro 'gid_t'
#define gid_t int
              ^
2 errors generated.

which happened because it could not find uid_t:

configure:5241: checking for uid_t in sys/types.h
./configure: line 5252: -I/opt/local/include: No such file or directory
configure:5262: result: no

But I don't know yet why that happened.

There is no problem when the configure script was generated with autoconf 2.69 so something about your configure.ac file is probably incompatible with autoconf 2.71 and needs to be fixed, but I don't know what yet.

[ryandesign]

./configure: line 5252: -I/opt/local/include: No such file or directory

This happens because it's trying to pass -I/opt/local/include and other flags to the C preprocessor but it hasn't yet determined what the C preprocessor is so that variable is empty and so it tries to run -I/opt/local/include as a command which obviously does not work. This is fixed by adding the line AC_PROG_CPP to configure.ac however that does not yet fix the original problem.

[ryandesign]

AC_TYPE_UID_T uses $EGREP but the configure script hasn't yet located a working egrep. Adding AC_PROG_EGREP to configure.ac results in a successful configure and build. I'll submit a PR for this and other modernizations suggested by autoupdate.