Clean up configure.ac, and be more strict about errors

.gitignore

@@ -19,3 +19,5 @@ configure
 config.h
 stamp-h1
 \.test_env/
+libtool.m4
+lt*.m4

.travis.yml

@@ -30,7 +30,7 @@ install:
 # use an explicit /usr/bin path when running the tests.
 script:
   - ./autogen.sh
-  - ./configure
+  - ./configure --disable-silent-rules --enable-werror
   - make $MAKEOPTS
   - file ./src/pyflame
   - ./runtests.sh -v /usr/bin/"${PYVERSION}"

configure.ac

@@ -14,10 +14,12 @@ AS_CASE([$host_os],
         [linux-gnu*], [],
         [AC_MSG_ERROR([Pyflame can only be built for Linux hosts])])
 
+enable_threads=no
 AS_IF([test x"$host_cpu" = xx86_64],
       [AC_MSG_NOTICE([x86-64 system, threads will be supported])
        AC_DEFINE([ENABLE_THREADS], [1], [Threads are enabled.])
        AC_DEFINE([USE_ELF64], [1], [Expect 64-bit ELF symbols.])
+       enable_threads=yes;
       ],
       [AC_MSG_NOTICE([Threading support will be disabled (only works on x86-64)])
        AC_DEFINE([ENABLE_THREADS], [0], [Threads are enabled.])
@@ -26,7 +28,10 @@ AS_IF([test x"$host_cpu" = xx86_64],
 
 AC_DEFINE_UNQUOTED([HOST_CPU], ["$host_cpu"], [CPU of target architecture.])
 
-AM_INIT_AUTOMAKE([dist-bzip2 foreign subdir-objects -Wall -Werror])
+AM_INIT_AUTOMAKE([dist-bzip2 foreign subdir-objects])
+
+dnl make the compilation flags quiet unless V=1 is used
+m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
 # Checks for programs.
 AC_PROG_CXX
@@ -44,26 +49,35 @@ LT_INIT
 # Ensure Linux kernel headers are present
 AC_CHECK_HEADERS([linux/ptrace.h], [], [AC_MSG_ERROR([Linux kernel headers missing])])
 
-AC_LANG([C++])
+AC_LANG_PUSH([C++])
 
-# This is commented out because it doesn't work right on Ubuntu 12.04 (Precise)
-# AX_CXX_COMPILE_STDCXX_11
+# Minimum C++ version is C++11
 AX_CHECK_COMPILE_FLAG(["-std=c++11"],
                       [AX_APPEND_FLAG(["-std=c++11"], [CXXFLAGS])],
-                      [AX_CHECK_COMPILE_FLAG(["-std=c++0x"],
-                                             [AX_APPEND_FLAG(["-std=c++0x"], [CXXFLAGS])],
-                                             [AC_MSG_ERROR([failed to detect C++11 support])])])
+                      [AC_MSG_ERROR([failed to detect C++11 support])])
+
+# Yes please.
+AX_APPEND_COMPILE_FLAGS([-Wall], [CXXFLAGS])
+
+# Turn warnings into errors
+AC_ARG_ENABLE([werror],
+              [AS_HELP_STRING([--enable-werror],
+              [Treat certain compiler warnings as errors (default is no)])],
+              [enable_werror=$enableval],
+              [enable_werror=no])
 
-AX_CHECK_COMPILE_FLAG([-Wall],
-                      [AX_APPEND_FLAG([-Wall], [CXXFLAGS])])
+if test "x$enable_werror" = "xyes"; then
+  AX_APPEND_COMPILE_FLAGS([-Werror], [CXXFLAGS])
+fi
 
 # Checks for libraries.
 
 # Checks for header files.
-AC_CHECK_HEADERS([fcntl.h limits.h unistd.h])
+AC_CHECK_HEADERS([fcntl.h limits.h sys/time.h unistd.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_CHECK_HEADER_STDBOOL
+AC_C_INLINE
 AC_TYPE_PID_T
 AC_TYPE_SIZE_T
 AC_TYPE_SSIZE_T
@@ -86,15 +100,18 @@ AC_DEFINE_UNQUOTED(
   ["$versionstr"],
   [A string containing build information.])
 
+enable_py26=no
 PKG_CHECK_MODULES([PY26], [python2], [enable_py26="yes"], [AC_MSG_WARN([Building without Python 2.6/2.7 support])])
 AM_CONDITIONAL([ENABLE_PY26], [test x"$enable_py26" = xyes])
 AM_COND_IF([ENABLE_PY26], [AC_DEFINE([ENABLE_PY26], [1], [Python 2.6/2.7 will be enabled])])
 
+enable_py34=no
 PKG_CHECK_MODULES([PY34], [python-3.4], [enable_py34="yes"],
                           [PKG_CHECK_MODULES([PY34], [python-3.5], [enable_py34="yes"], [AC_MSG_WARN([Building without Python 3.4/3.5 support])])])
 AM_CONDITIONAL([ENABLE_PY34], [test x"$enable_py34" = xyes])
 AM_COND_IF([ENABLE_PY34], [AC_DEFINE([ENABLE_PY34], [1], [Python 3.4/3.5 will be enabled])])
 
+enable_py36=no
 PKG_CHECK_MODULES([PY36], [python-3.6], [enable_py36="yes"], [AC_MSG_WARN([Building without Python 3.6 support])])
 AM_CONDITIONAL([ENABLE_PY36], [test x"$enable_py36" = xyes])
 AM_COND_IF([ENABLE_PY36], [AC_DEFINE([ENABLE_PY36], [1], [Python 3.6 will be enabled])])
@@ -104,6 +121,19 @@ AS_IF([test x"$enable_py26" = xyes -o x"$enable_py34" = xyes -o x"$enable_py36"
       [AC_MSG_ERROR([Failed to find a supported Python.h])]
 )
 
-AC_CONFIG_FILES([Makefile
-                 src/Makefile])
+AC_LANG_POP
+
+AC_CONFIG_FILES([Makefile src/Makefile])
 AC_OUTPUT
+
+echo
+echo "Options used to compile and link:"
+echo
+echo "  with threads        = $enable_threads"
+echo "  with Python 2.6/7   = $enable_py26"
+echo "  with Python 3.4/5   = $enable_py34"
+echo "  with Python 3.6+    = $enable_py36"
+echo
+echo "  CXX                 = $CXX"
+echo "  CXXFLAGS            = $CXXFLAGS"
+echo

m4/ax_append_compile_flags.m4

@@ -0,0 +1,67 @@
+# ============================================================================
+#  https://www.gnu.org/software/autoconf-archive/ax_append_compile_flags.html
+# ============================================================================
+#
+# SYNOPSIS
+#
+#   AX_APPEND_COMPILE_FLAGS([FLAG1 FLAG2 ...], [FLAGS-VARIABLE], [EXTRA-FLAGS], [INPUT])
+#
+# DESCRIPTION
+#
+#   For every FLAG1, FLAG2 it is checked whether the compiler works with the
+#   flag.  If it does, the flag is added FLAGS-VARIABLE
+#
+#   If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
+#   CFLAGS) is used.  During the check the flag is always added to the
+#   current language's flags.
+#
+#   If EXTRA-FLAGS is defined, it is added to the current language's default
+#   flags (e.g. CFLAGS) when the check is done.  The check is thus made with
+#   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to
+#   force the compiler to issue an error when a bad flag is given.
+#
+#   INPUT gives an alternative input source to AC_COMPILE_IFELSE.
+#
+#   NOTE: This macro depends on the AX_APPEND_FLAG and
+#   AX_CHECK_COMPILE_FLAG. Please keep this macro in sync with
+#   AX_APPEND_LINK_FLAGS.
+#
+# LICENSE
+#
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 6
+
+AC_DEFUN([AX_APPEND_COMPILE_FLAGS],
+[AX_REQUIRE_DEFINED([AX_CHECK_COMPILE_FLAG])
+AX_REQUIRE_DEFINED([AX_APPEND_FLAG])
+for flag in $1; do
+  AX_CHECK_COMPILE_FLAG([$flag], [AX_APPEND_FLAG([$flag], [$2])], [], [$3], [$4])
+done
+])dnl AX_APPEND_COMPILE_FLAGS

m4/ax_require_defined.m4

@@ -0,0 +1,37 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_require_defined.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_REQUIRE_DEFINED(MACRO)
+#
+# DESCRIPTION
+#
+#   AX_REQUIRE_DEFINED is a simple helper for making sure other macros have
+#   been defined and thus are available for use.  This avoids random issues
+#   where a macro isn't expanded.  Instead the configure script emits a
+#   non-fatal:
+#
+#     ./configure: line 1673: AX_CFLAGS_WARN_ALL: command not found
+#
+#   It's like AC_REQUIRE except it doesn't expand the required macro.
+#
+#   Here's an example:
+#
+#     AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG])
+#
+# LICENSE
+#
+#   Copyright (c) 2014 Mike Frysinger <vapier@gentoo.org>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 2
+
+AC_DEFUN([AX_REQUIRE_DEFINED], [dnl
+  m4_ifndef([$1], [m4_fatal([macro ]$1[ is not defined; is a m4 file missing?])])
+])dnl AX_REQUIRE_DEFINED

src/frob.cc

@@ -16,6 +16,13 @@
 // frob3.cc, which define PYFLAME_PY_VERSION. Since Makefile.am for more
 // information.
 
+#include <Python.h>
+#include <frameobject.h>
+
+#if PYFLAME_PY_VERSION >= 34
+#include <unicodeobject.h>
+#endif
+
 #include <sys/types.h>
 #include <algorithm>
 #include <cstddef>
@@ -25,13 +32,6 @@
 #include <sstream>
 #include <string>
 
-#include <Python.h>
-#include <frameobject.h>
-
-#if PYFLAME_PY_VERSION >= 34
-#include <unicodeobject.h>
-#endif
-
 #include "./config.h"
 #include "./exc.h"
 #include "./ptrace.h"