Update and improve autotools build

- INCLUDES is deprecated, and CPPFLAGS is an user-defined
  variable, use the proper AM_CPPFLAGS instead

- Remove FLAC__INLINE definition, providing proper
  replacement for MSVC compilers.

- Detect if we have C99 's lround and provide a replacement
  for windows...

src/share/getopt/Makefile.am

@@ -2,7 +2,7 @@
 
 AUTOMAKE_OPTIONS = foreign
 
-INCLUDES = -I$(top_srcdir)/include/share
+AM_CPPFLAGS = -I$(top_builddir) -I$(srcdir)/include -I$(top_srcdir)/include -I$(top_srcdir)/include/share
 
 noinst_LIBRARIES = libgetopt.a
 

src/share/grabbag/Makefile.am

@@ -2,7 +2,7 @@
 
 AUTOMAKE_OPTIONS = foreign
 
-INCLUDES = -I$(top_srcdir)/include
+AM_CPPFLAGS = -I$(top_builddir) -I$(srcdir)/include -I$(top_srcdir)/include
 
 noinst_LTLIBRARIES = libgrabbag.la
 

src/share/replaygain_analysis/Makefile.am

@@ -2,7 +2,7 @@
 
 AUTOMAKE_OPTIONS = foreign
 
-INCLUDES = -I$(top_srcdir)/include/share
+AM_CPPFLAGS = -I$(top_builddir) -I$(srcdir)/include -I$(top_srcdir)/include -I$(top_srcdir)/include/share
 
 noinst_LTLIBRARIES = libreplaygain_analysis.la
 

src/share/replaygain_synthesis/Makefile.am

@@ -4,7 +4,7 @@ AUTOMAKE_OPTIONS = foreign
 
 SUBDIRS = include .
 
-INCLUDES = -I$(top_srcdir)/include -I$(top_srcdir)/include/share
+AM_CPPFLAGS = -I$(top_builddir) -I$(srcdir)/include -I$(top_srcdir)/include -I$(top_srcdir)/include/share
 
 noinst_LTLIBRARIES = libreplaygain_synthesis.la
 

src/share/utf8/Makefile.am

@@ -2,7 +2,7 @@
 
 AUTOMAKE_OPTIONS = foreign
 
-INCLUDES = -I$(top_srcdir)/include/share
+AM_CPPFLAGS = -I$(top_builddir) -I$(srcdir)/include -I$(top_srcdir)/include -I$(top_srcdir)/include/share
 
 noinst_LTLIBRARIES = libutf8.la