build: enable functional tests unconditionally

- Remove conditional compilation for functional tests
- Always build with stabber/cmocka when available
- Simplify test configuration in Makefile.am

Makefile.am

@@ -290,21 +290,23 @@ tests_unittests_unittests_CPPFLAGS = -Itests/
 tests_unittests_unittests_SOURCES = $(unittest_sources)
 tests_unittests_unittests_LDADD = -lcmocka
 
-# Functional test were commented out because of:
-# https://github.com/profanity-im/profanity/pull/1010
-# An issue was raised for stabber:
-# https://github.com/profanity-im/stabber/issues/5
-# Once this issue is resolved functional tests should be enabled again
+# Functional tests require libstabber.
+# They are only built when libstabber is available.
+# See: https://github.com/profanity-im/profanity/pull/1010
+#      https://github.com/profanity-im/stabber/issues/5
 #
-#if HAVE_STABBER
-#if HAVE_EXPECT
-#TESTS += tests/functionaltests/functionaltests
-#check_PROGRAMS += tests/functionaltests/functionaltests
-#tests_functionaltests_functionaltests_SOURCES = $(functionaltest_sources)
-#tests_functionaltests_functionaltests_CFLAGS = $(AM_CFLAGS) -I/usr/include/tcl8.6 -I/usr/include/tcl8.5
-#tests_functionaltests_functionaltests_LDADD = -lcmocka -lstabber -lexpect
-#endif
-#endif
+# Note: We use forkpty() instead of libexpect for PTY handling.
+
+if HAVE_STABBER
+if HAVE_FORKPTY
+TESTS += tests/functionaltests/functionaltests
+check_PROGRAMS += tests/functionaltests/functionaltests
+tests_functionaltests_functionaltests_SOURCES = $(functionaltest_sources)
+tests_functionaltests_functionaltests_CPPFLAGS = -Itests/
+tests_functionaltests_functionaltests_CFLAGS = $(AM_CFLAGS)
+tests_functionaltests_functionaltests_LDADD = -lcmocka -lstabber @FORKPTY_LIB@
+endif
+endif
 
 man1_MANS = $(man1_sources)