THRIFT-507. Only use Boost for building the C++ library

- Make AX_BOOST_BASE warn instead of fataling if Boost is not found.
- If Boost is not found, disable compilation of the C++ library.
- Do not use CPPFLAGS or LDFLAGS from Boost when building the compiler.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@991253 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/Makefile.am b/compiler/cpp/Makefile.am
index 4e7b9c0..6d0d409 100644
--- a/compiler/cpp/Makefile.am
+++ b/compiler/cpp/Makefile.am
@@ -108,8 +108,8 @@
 thrift_SOURCES += src/generate/t_js_generator.cc
 endif
 
-thrift_CXXFLAGS = -Wall -I$(srcdir)/src $(BOOST_CPPFLAGS)
-thrift_LDFLAGS = -Wall $(BOOST_LDFLAGS)
+thrift_CXXFLAGS = -Wall -I$(srcdir)/src
+thrift_LDFLAGS = -Wall
 
 thrift_LDADD = @LEXLIB@