gnulib and emscripten

[Bruno Haible]

Hi,

emscripten [1][2] is a C runtime environment, where execution takes place in
JavaScript (NodeJS by default, but some things can also run inside a web
browser).

Just to see how it works out, I built it using the GNU Taler instructions
[3], created a gnulib testdir
  $ ./gnulib-tool --create-testdir --dir=testdir-posix --with-tests 
--single-configure `./posix-modules`
and ran it
  $ emconfigure ./configure --host=asmjs-local-emscripten
  $ emmake make

Observations
============

I. During the configure run:

I.1. getuid() apparently returns 0, which causes a test to bark:
checking whether mknod can create fifo without root privileges... configure: 
error: in `/media/private+free/devel/GNULIB/testdir-posix-20170210':
configure: error: you should not run configure as root (set 
FORCE_UNSAFE_CONFIGURE=1 in environment to bypass this check)
See `config.log' for more details
ERROR:root:Configure step failed with non-zero return code 1! Command line: 
['./configure', '--host=asmjs-local-emscripten'] at 
/media/private+free/devel/GNULIB/testdir-posix-20170210

I have to set FORCE_UNSAFE_CONFIGURE=1.

I.2. checking for working nanosleep... hangs (eating 100% CPU time)
I.3. checking for working sleep... hangs (eating 100% CPU time)

This looks like a bug in the sleep() and nanosleep() functions.

II. "make" failures:

II.1. In module 'fseeko':

fseeko.c:110:4: error: "Please port gnulib fseeko.c to your platform! Look at 
the code in fseeko.c, then report this to bug-gnulib."
  #error "Please port gnulib fseeko.c to your platform! Look at the code in 
fseeko.c, then report this to bug-gnulib."
   ^
1 error generated.

II.2. In module 'glob':

glob.c:772:27: error: use of undeclared identifier 'malloc_pwtmpbuf'
                      if (malloc_pwtmpbuf == NULL)
                          ^
glob.c:785:41: error: use of undeclared identifier 'pwtmpbuf'
                                  free (pwtmpbuf);
                                        ^
glob.c:793:33: error: use of undeclared identifier 'pwtmpbuf'
                          free (pwtmpbuf);
                                ^
glob.c:1003:31: error: use of undeclared identifier 'malloc_pwtmpbuf'
                        free (malloc_pwtmpbuf);
                              ^
glob.c:1015:23: error: use of undeclared identifier 'malloc_pwtmpbuf'
                free (malloc_pwtmpbuf);
                      ^
glob.c:1019:23: error: use of undeclared identifier 'malloc_pwtmpbuf'
                free (malloc_pwtmpbuf);
                      ^
6 errors generated.

This looks like it is caused by the 2016-05-04 merge from glibc.
These two variables are declared only
   if defined HAVE_GETPWNAM_R || defined _LIBC
but then are used unconditionally.

II.3. In module 'tsearch':

In file included from tsearch.c:98:
./search.h:416:3: error: redefinition of enumerator 'preorder'
  preorder,
  ^
/media/private+free/devel/emsdk_portable/emscripten/master/system/include/libc/search.h:14:16:
 note: previous definition is here
typedef enum { preorder, postorder, endorder, leaf } VISIT;
               ^
In file included from tsearch.c:98:
./search.h:417:3: error: redefinition of enumerator 'postorder'
  postorder,
  ^
/media/private+free/devel/emsdk_portable/emscripten/master/system/include/libc/search.h:14:26:
 note: previous definition is here
typedef enum { preorder, postorder, endorder, leaf } VISIT;
                         ^
In file included from tsearch.c:98:
./search.h:418:3: error: redefinition of enumerator 'endorder'
  endorder,
  ^
/media/private+free/devel/emsdk_portable/emscripten/master/system/include/libc/search.h:14:37:
 note: previous definition is here
typedef enum { preorder, postorder, endorder, leaf } VISIT;
                                    ^
In file included from tsearch.c:98:
./search.h:419:3: error: redefinition of enumerator 'leaf'
  leaf
  ^
/media/private+free/devel/emsdk_portable/emscripten/master/system/include/libc/search.h:14:47:
 note: previous definition is here
typedef enum { preorder, postorder, endorder, leaf } VISIT;
                                              ^
In file included from tsearch.c:98:
./search.h:421:1: error: typedef redefinition with different types ('enum 
VISIT' vs 'enum VISIT')
VISIT;
^
/media/private+free/devel/emsdk_portable/emscripten/master/system/include/libc/search.h:14:54:
 note: previous definition is here
typedef enum { preorder, postorder, endorder, leaf } VISIT;
                                                     ^
5 errors generated.

The reason is that this system has <search.h>, and it defines the 'VISIT' enum,
but it does not have the tsearch() function.

III. "make check" trouble

"emmake make check" does not generate executable files. To get something 
executable,
I had to
  - change EXEEXT = .js in Makefile,
  - run the tests through a shell loop:
    $ for f in test-*.js ; do echo $f ; node $f ; echo $?; done


I'm fixing only the 'tsearch' bug.


[1] https://en.wikipedia.org/wiki/Emscripten
[2] https://github.com/kripken/emscripten
[3] https://git.taler.net/libtalerutil-emscripten.git/tree/README

0001-search-Don-t-assume-that-tsearch-exists-if-VISIT-is-.patch
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