Add prelim backtrace support detection in build

Makefile.am

@@ -27,7 +27,6 @@ UTIL_INCLUDE =  \
     version.hpp
 
 UTIL_FILES   =	\
-    backtrace.cpp \
     debug.cpp   \
     except.cpp  \
     float.cpp	\
@@ -44,6 +43,12 @@ UTIL_FILES   =	\
     vector.cpp  \
     version.cpp
 
+
+if HAVE_EXECINFO
+UTIL_FILES += backtrace_execinfo.cpp
+endif
+
+
 CLEANFILES = json.cpp version.cpp ip.cpp
 EXTRA_DIST = json.cpp.rl version.cpp.rl ip.cpp.rl
 

configure.ac

@@ -67,9 +67,13 @@ AC_C_INLINE
 AC_C_BIGENDIAN
 
 ##
-## stdlib features
+## platform features
 AC_FUNC_MMAP
 
+AC_CHECK_HEADER([execinfo.h], [break], [AC_MSG_ERROR([Missing backtrace support])])
+
+AM_CONDITIONAL([HAVE_EXECINFO], [test x$ac_cv_header_execinfo_h = "xyes"])
+
 
 ##
 ## Documentation