Create vltstd to isolate duplicated headers

Makefile.in

@@ -113,6 +113,7 @@ DISTFILES_INC = $(INFOS) .gitignore Artistic COPYING COPYING.LESSER \
 	include/*.[chv]* \
 	include/*.in \
 	include/.*ignore \
+	include/vltstd/*.[chv]* \
 	.*attributes */.*attributes  */*/.*attributes \
 	src/.*ignore src/*.in src/*.cpp src/*.[chly] src/astgen src/bisonpre src/*fix \
 	src/*.pl src/*.pod \
@@ -258,9 +259,10 @@ installman: $(VL_INST_MAN_FILES)
 	done
 
 installdata:
-	$(SHELL) ${srcdir}/mkinstalldirs $(DESTDIR)$(pkgdatadir)/include $(DESTDIR)$(pkgdatadir)/examples
-	cp -r include/* $(DESTDIR)$(pkgdatadir)/include
-	cp -r ${srcdir}/include/* $(DESTDIR)$(pkgdatadir)/include
+	$(SHELL) ${srcdir}/mkinstalldirs $(DESTDIR)$(pkgdatadir)/include/vltstd $(DESTDIR)$(pkgdatadir)/examples
+	cp -r include/*.* $(DESTDIR)$(pkgdatadir)/include
+	cp -r ${srcdir}/include/*.* $(DESTDIR)$(pkgdatadir)/include
+	cp -r ${srcdir}/include/vltstd/*.* $(DESTDIR)$(pkgdatadir)/include/vltstd
 	cp -r ${srcdir}/test_c  $(DESTDIR)$(pkgdatadir)/examples
 	cp -r ${srcdir}/test_sc $(DESTDIR)$(pkgdatadir)/examples
 	cp -r ${srcdir}/test_sp $(DESTDIR)$(pkgdatadir)/examples

bin/verilator

@@ -1286,6 +1286,17 @@ The /*verilator sformat*/ indicates that this function accepts a $display
 like format specifier followed by any number of arguments to satisfy the
 format.
 
+=head2 DPI Header Isolation
+
+Verilator places the IEEE standard header files such as svdpi.h into a
+separate include directory, vltstd (VeriLaTor STandarD).  When compiling
+most applications $VERILATOR_ROOT/include/vltstd would be in the include
+path along with the normal $VERILATOR_ROOT/include.  However, when
+compiling Verilated models into other simulators which have their own
+svdpi.h and similar standard files with different contents, the vltstd
+directory should not be included to prevent picking up incompatible
+definitions.
+
 =head2 Public Functions 
 
 Instead of DPI exporting, there's also Verilator public functions, which

include/verilated.mk.in

@@ -26,6 +26,7 @@ SP_INCLUDER     = $(PERL) $(VERILATOR_ROOT)/bin/verilator_includer
 VK_CPPFLAGS_ALWAYS += \
 		-MMD \
 		-I$(VERILATOR_ROOT)/include \
+		-I$(VERILATOR_ROOT)/include/vltstd \
 		-DVL_PRINTF=printf \
 		-DVM_TRACE=$(VM_TRACE) \
 		-DVM_COVERAGE=$(VM_COVERAGE) \
@@ -44,6 +45,7 @@ CPPFLAGS += -I. $(VK_CPPFLAGS_ALWAYS) $(VK_CPPFLAGS_WALL)
 
 VPATH += ..
 VPATH += $(VERILATOR_ROOT)/include
+VPATH += $(VERILATOR_ROOT)/include/vltstd
 
 #OPT = -ggdb -DPRINTINITSTR -DDETECTCHANGE
 #OPT = -ggdb -DPRINTINITSTR

include/verilated_dpi.cpp

@@ -32,7 +32,7 @@
 #define XXTERN DPI_EXTERN DPI_DLLESPEC
 #define EETERN DPI_EXTERN DPI_DLLESPEC
 
-#include "svdpi.h"
+#include "vltstd/svdpi.h"
 
 //======================================================================
 // Internal macros