configure: Test for compiler flags, and remove old config checks

configure.ac

@@ -94,21 +94,41 @@ fi
 
 # Checks for libraries.
 
-# Checks for header files.
-AC_HEADER_STDC
-AC_HEADER_SYS_WAIT
-AC_CHECK_HEADERS(fcntl.h unistd.h inttypes.h sys/file.h sys/time.h sys/un.h math.h stdint.h mingw/stdint.h)
-
 # Checks for typedefs, structures
 AC_CHECK_TYPE(size_t,unsigned int)
-AC_CHECK_TYPE(uint_t,unsigned int)
-AC_CHECK_TYPE(ulong_t,unsigned long)
 AC_TYPE_SIZE_T
-AC_STRUCT_TM
 
 # Checks for compiler characteristics.
 AC_C_INLINE
 
+AC_DEFUN([_MY_CXX_CHECK_OPT],
+   [# _MY_CXX_CHECK_OPT(flag) -- Check if compiler supports specific options
+    ACO_SAVE_CXXFLAGS="$CXXFLAGS"
+    # -Werror needed otherwise unknown -Wno-div-by-zero won't report problems
+    CXXFLAGS="$CXXFLAGS $1 -Werror"
+    AC_MSG_CHECKING([whether $CXX accepts $1])
+    AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([],[])],
+	 [_my_result=yes],
+	 [_my_result=no])
+    AC_MSG_RESULT($_my_result)
+    if test "$_my_result" = "yes" ; then
+       CFG_CXXFLAGS_NO_UNUSED="$CFG_CXXFLAGS_NO_UNUSED $1"
+    fi
+    CXXFLAGS="$ACO_SAVE_CXXFLAGS"
+   ])# _MY_CXX_CHECK_OPT
+
+# For example, -Wno-div-by-zero isn't in 4.1.2
+_MY_CXX_CHECK_OPT(-Wno-char-subscripts)
+# Random code often does / 0.  Unfortunately VL_DIV_I(0,0) will warn
+# without this flag, even though there's a conditional to prevent the divide.
+_MY_CXX_CHECK_OPT(-Wno-div-by-zero)
+_MY_CXX_CHECK_OPT(-Wno-sign-compare)
+_MY_CXX_CHECK_OPT(-Wno-uninitialized)
+_MY_CXX_CHECK_OPT(-Wno-unused-parameter)
+_MY_CXX_CHECK_OPT(-Wno-unused-variable)
+AC_SUBST(CFG_CXXFLAGS_NO_UNUSED)
+
 # Checks for library functions.
 
 # Checks for system services

include/verilated.mk.in

@@ -16,6 +16,9 @@ RANLIB = ranlib
 CFG_WITH_CCWARN = @CFG_WITH_CCWARN@
 CFG_WITH_LONGTESTS = @CFG_WITH_LONGTESTS@
 
+# Compiler flags to use to turn off unused and generated code warnings, such as -Wno-div-by-zero
+CFG_CXXFLAGS_NO_UNUSED = @CFG_CXXFLAGS_NO_UNUSED@
+
 ######################################################################
 # Programs
 
@@ -43,11 +46,7 @@ VK_CPPFLAGS_ALWAYS += \
 
 ifeq ($(CFG_WITH_CCWARN),yes)	# Local... Else don't burden users
 VK_CPPFLAGS_WALL += -Wall \
-		-Wno-char-subscripts \
-		-Wno-sign-compare \
-		-Wno-unused-parameter \
-		-Wno-unused-variable \
-		-Wno-uninitialized \
+		$(CFG_CXXFLAGS_NO_UNUSED) \
 		-Werror
 endif
 

src/config_build.h.in

@@ -33,36 +33,9 @@
 //**********************************************************************
 //**** Functions
 
-// Set define if we have function: strdup (string)
-#define HAVE_STRDUP 0
-
 //**********************************************************************
 //**** Headers
 
-// Set define if we have header: <fcntl.h>
-#define HAVE_FCNTL_H 0
-
-// Set define if we have header: <math.h>
-#define HAVE_MATH_H 1
-
-// Set define if we have header: <unistd.h>
-#define HAVE_UNISTD_H 0
-
-// Set define if we have header: <sys/time.h>
-#define HAVE_SYS_TIME_H 0
-
-// Set define if we have header: <sys/un.h>
-#define HAVE_SYS_UN_H 0
-
-// Set define if we have header: <stdint.h>
-#define HAVE_STDINT_H 0
-
-// Set define if we have header: <mingw/stdint.h>
-#define HAVE_MINGW_STDINT_H 0
-
-// Set define if we have header: <inttypes.h>
-#define HAVE_INTTYPES_H 0
-
 //**********************************************************************
 //**** Default environment
 

test_verilated/Makefile_obj

@@ -22,10 +22,6 @@ include Vvgen.mk
 CPPFLAGS += -DVL_DEBUG=1
 CPPFLAGS += $(CPPFLAGS_ADD)
 
-# Random code often does / 0.  Unfortunately VL_DIV_I(0,0) will warn
-# without this flag, even though there's a conditional to prevent the divide.
-CPPFLAGS += -Wno-div-by-zero
-
 #######################################################################
 # Linking final exe -- presumes have a sim_main.cpp