lib/msun/tests: Add more debug output to fenv_test.c

Output a hex dump of the current fenv and the expected value to allow
comparing them without having to resort to interactive use of GDB.

lib/msun/tests/Makefile

@@ -86,6 +86,7 @@ IGNORE_PRAGMA=
 
 SRCS.ilogb2_test=	ilogb_test.c
 
+LIBADD.fenv_test+=	util
 LIBADD+=	m
 
 WARNS?=		6

lib/msun/tests/fenv_test.c

@@ -37,6 +37,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <fenv.h>
 #include <float.h>
+#include <libutil.h>
 #include <math.h>
 #include <signal.h>
 #include <stdio.h>
@@ -173,7 +174,10 @@ ATF_TC_BODY(dfl_env, tc)
 	fenv_t env;
 
 	fegetenv(&env);
-
+	/* Print the default environment for debugging purposes. */
+	hexdump(&env, sizeof(env), "current fenv ", HD_OMIT_CHARS);
+	hexdump(FE_DFL_ENV, sizeof(env), "default fenv ", HD_OMIT_CHARS);
+	CHECK_FP_EXCEPTIONS(0, FE_ALL_EXCEPT);
 #ifdef __amd64__
 	/*
 	 * Compare the fields that the AMD [1] and Intel [2] specs say will be
@@ -202,7 +206,7 @@ ATF_TC_BODY(dfl_env, tc)
 #endif
 
 #endif
-	ATF_CHECK_EQ(0, fetestexcept(FE_ALL_EXCEPT));
+	CHECK_FP_EXCEPTIONS(0, FE_ALL_EXCEPT);
 }
 
 /*