Check existence of required tr headers

.gitignore

@@ -39,5 +39,3 @@ gmon.out
 test-driver
 /assets/html/_documentation.html
 tags
-/trevent.h
-/trevent.h.in

configure.ac

@@ -12,7 +12,7 @@ AM_SILENT_RULES([yes])
 AC_COPYRIGHT([Copyright © 2014 Georg Hopp])
 AC_REVISION([0.0.0])
 AC_CONFIG_SRCDIR([src/event.c])
-AC_CONFIG_HEADERS([trevent.h])
+AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 
 m4_include([m4/gcov.m4])
@@ -41,7 +41,20 @@ AM_COND_IF([HAVE_DOXYGEN],
 	   [AC_CONFIG_FILES([docs/Doxyfile])])
 
 # Checks for header files.
-AC_CHECK_HEADERS([stdarg.h string.h stdlib.h stdio.h unistd.h syslog.h sys/types.h])
+AC_CHECK_HEADERS([stdarg.h string.h stdlib.h stdio.h unistd.h syslog.h \
+		  sys/types.h])
+AC_CHECK_HEADER(trbase.h, [], [
+	AC_MSG_ERROR([unable to find the trbase header])
+])
+AC_CHECK_HEADER(trio.h, [], [
+	AC_MSG_ERROR([unable to find the trio header])
+])
+AC_CHECK_HEADER(trhash.h, [], [
+	AC_MSG_ERROR([unable to find the trhash header])
+])
+AC_CHECK_HEADER(trdata.h, [], [
+	AC_MSG_ERROR([unable to find the trdata header])
+])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_HEADER_STDBOOL