diff --git a/modules/libcom/src/flex/Makefile b/modules/libcom/src/flex/Makefile
index 20cce5d30..5c6f41bfe 100644
--- a/modules/libcom/src/flex/Makefile
+++ b/modules/libcom/src/flex/Makefile
@@ -29,7 +29,6 @@ e_flex_SRCS += nfa.c
 e_flex_SRCS += sym.c
 e_flex_SRCS += tblcmp.c
 e_flex_SRCS += parse.c
-e_flex_OBJS += epicsTempFile$(OBJ)
 
 PROD_HOST += e_flex
 
diff --git a/modules/libcom/src/flex/flex.c b/modules/libcom/src/flex/flex.c
index faf61ed19..6abb9597f 100644
--- a/modules/libcom/src/flex/flex.c
+++ b/modules/libcom/src/flex/flex.c
@@ -43,8 +43,14 @@ char copyright[] =
 #endif /* not lint */
 
 
-#include "epicsTempFile.h"
-#undef epicsExportSharedSymbols
+#ifdef EPICS_BUILD_DLL
+#  undef EPICS_BUILD_DLL
+#endif
+#ifdef EPICS_CALL_DLL
+#  undef EPICS_CALL_DLL
+#endif
+
+#include "epicsTempFile.c"
 
 static char flex_version[] = "2.3";
 
diff --git a/modules/libcom/src/flex/flexdef.h b/modules/libcom/src/flex/flexdef.h
index cf972b274..c14260ccb 100644
--- a/modules/libcom/src/flex/flexdef.h
+++ b/modules/libcom/src/flex/flexdef.h
@@ -43,6 +43,12 @@
 #include <stdlib.h>
 #include <ctype.h>
 
+#ifdef _WIN32
+#  include <io.h>
+#else
+#  include <unistd.h>
+#endif
+
 #ifdef __GNUC__
 #define NORETURN __attribute__((noreturn))
 #else
@@ -824,12 +830,5 @@ extern int yylex ();
 
 /* The Unix kernel calls used here */
 
-extern int read (int, char*, int);
-#ifndef _WIN32
-extern int unlink (char*);
-#endif
-extern int write (int, char*, int);
-
-
 #endif /* INC_flexdef_H */
 
diff --git a/modules/libcom/src/yacc/antelope.c b/modules/libcom/src/yacc/antelope.c
index 5475874ed..620035799 100644
--- a/modules/libcom/src/yacc/antelope.c
+++ b/modules/libcom/src/yacc/antelope.c
@@ -10,6 +10,13 @@
 #include "defs.h"
 
 /* Need this before the Com library can build it */
+#ifdef EPICS_BUILD_DLL
+#  undef EPICS_BUILD_DLL
+#endif
+#ifdef EPICS_CALL_DLL
+#  undef EPICS_CALL_DLL
+#endif
+
 #include "epicsTempFile.c"
 
 char dflag;