fix(tests): replace libexpect with forkpty() for functional tests

Remove dependency on libexpect which had a segfault bug on Arch Linux.

- Replace exp_spawnl() with forkpty() for PTY creation
- Replace exp_expectl() with custom POSIX regex matching
- Update configure.ac to check for forkpty() instead of libexpect
- Update Makefile.am to link with libutil instead of libexpect/libtcl
- Remove expect/tcl packages from all Dockerfiles
- Add Valgrind suppressions for stabber/pthread false positives

configure.ac

@@ -374,13 +374,13 @@ PKG_CHECK_MODULES([cmocka], [cmocka], [],
 AM_CONDITIONAL([HAVE_STABBER], [false])
 AC_CHECK_LIB([stabber], [stbbr_start], [AM_CONDITIONAL([HAVE_STABBER], [true])],
     [AC_MSG_NOTICE([libstabber not found, will not be able to run functional tests])])
-AM_CONDITIONAL([HAVE_EXPECT], [false])
-dnl libexpect on Debian/Ubuntu requires -ltcl8.6 for linking
-saved_LIBS="$LIBS"
-LIBS="$LIBS -ltcl8.6"
-AC_CHECK_LIB([expect], [exp_expectl], [AM_CONDITIONAL([HAVE_EXPECT], [true])],
-    [AC_MSG_NOTICE([libexpect not found, will not be able to run functional tests])])
-LIBS="$saved_LIBS"
+dnl Check for forkpty (needed for functional tests PTY handling)
+dnl On Linux it's in libutil, on some BSDs it's in libc
+AM_CONDITIONAL([HAVE_FORKPTY], [false])
+AC_CHECK_LIB([util], [forkpty], [AM_CONDITIONAL([HAVE_FORKPTY], [true]) FORKPTY_LIB="-lutil"],
+    [AC_CHECK_FUNC([forkpty], [AM_CONDITIONAL([HAVE_FORKPTY], [true]) FORKPTY_LIB=""],
+        [AC_MSG_NOTICE([forkpty not found, will not be able to run functional tests])])])
+AC_SUBST([FORKPTY_LIB])
 
 ## Default parameters
 AM_CFLAGS="$AM_CFLAGS -Wall -Wno-deprecated-declarations -std=gnu99 -ggdb3"