#408 Build failure due to implicit declaration of functions
Hi, joe 4.6 fails to build with Xcode 12 on macOS due to implicit declaration of functions (which have not been allowed ever since C99 but which now in Xcode 12 have been changed from a warning to an actual error).
This was reported to MacPorts here: https://trac.macports.org/ticket/61627
First there are three places where the configure script uses the exit function without including the header that defines exit, causing three errors in the config.log:
conftest.c:56:2: error: implicitly declaring library function 'exit' with type 'void (int) __attribute__((noreturn))' [-Werror,-Wimplicit-function-declaration]
conftest.c:65:3: error: implicitly declaring library function 'exit' with type 'void (int) __attribute__((noreturn))' [-Werror,-Wimplicit-function-declaration]
conftest.c:145:2: error: implicitly declaring library function 'exit' with type 'void (int) __attribute__((noreturn))' [-Werror,-Wimplicit-function-declaration]
This doesn't cause configuration to abort but causes the results of those three configure tests to be wrong so they should be fixed. The simplest fix is to replace exit with return. If for some reason you prefer to use exit, add #include <stdlib.h> to each test.
Then the build actually fails later with:
tty.c:975:6: error: implicit declaration of function 'openpty' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
tty.c:1221:6: error: implicit declaration of function 'login_tty' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
On macOS this was fixed by adding #include <util.h> to the file. Not sure whether those are in different files on different operating systems.
The full fix I applied to MacPorts is:
This was fixed in Mercurial and in the new git repo with this commit
This is not yet fixed since
#include <util.h>is not imported on mac.Reopening in that case.