diff --git a/nsprpub/pr/include/prlock.h b/nsprpub/pr/include/prlock.h
index 05e59446eded..0017f71dcf98 100644
--- a/nsprpub/pr/include/prlock.h
+++ b/nsprpub/pr/include/prlock.h
@@ -61,7 +61,7 @@ typedef struct PRLock PRLock;
 **   is returned.
 **  
 ***********************************************************************/
-PR_EXTERN(PRLock*) PR_NewLock(void);
+NSPR_API(PRLock*) PR_NewLock(void);
 
 /***********************************************************************
 ** FUNCTION:    PR_DestroyLock
@@ -72,7 +72,7 @@ PR_EXTERN(PRLock*) PR_NewLock(void);
 ** OUTPUTS:     void
 ** RETURN:      None
 ***********************************************************************/
-PR_EXTERN(void) PR_DestroyLock(PRLock *lock);
+NSPR_API(void) PR_DestroyLock(PRLock *lock);
 
 /***********************************************************************
 ** FUNCTION:    PR_Lock
@@ -83,7 +83,7 @@ PR_EXTERN(void) PR_DestroyLock(PRLock *lock);
 ** OUTPUTS:     void
 ** RETURN:      None
 ***********************************************************************/
-PR_EXTERN(void) PR_Lock(PRLock *lock);
+NSPR_API(void) PR_Lock(PRLock *lock);
 
 /***********************************************************************
 ** FUNCTION:    PR_Unlock
@@ -95,7 +95,7 @@ PR_EXTERN(void) PR_Lock(PRLock *lock);
 ** RETURN:      PR_STATUS
 **              Returns PR_FAILURE if the caller does not own the lock.
 ***********************************************************************/
-PR_EXTERN(PRStatus) PR_Unlock(PRLock *lock);
+NSPR_API(PRStatus) PR_Unlock(PRLock *lock);
 
 PR_END_EXTERN_C
 
diff --git a/nsprpub/pr/include/prtypes.h b/nsprpub/pr/include/prtypes.h
index 8aaf594ea75e..613aa9f79669 100644
--- a/nsprpub/pr/include/prtypes.h
+++ b/nsprpub/pr/include/prtypes.h
@@ -68,6 +68,11 @@
 #define _declspec(x) __declspec(x)
 #endif
 
+#define PR_EXPORT(__type) extern _declspec(dllexport) __type
+#define PR_EXPORT_DATA(__type) extern _declspec(dllexport) __type
+#define PR_IMPORT(__type) _declspec(dllimport) __type
+#define PR_IMPORT_DATA(__type) _declspec(dllimport) __type
+
 #define PR_EXTERN(__type) extern _declspec(dllexport) __type
 #define PR_IMPLEMENT(__type) _declspec(dllexport) __type
 #define PR_EXTERN_DATA(__type) extern _declspec(dllexport) __type
@@ -78,6 +83,12 @@
 #define PR_STATIC_CALLBACK(__x) static __x
 
 #elif defined(XP_BEOS)
+
+#define PR_EXPORT(__type) extern _declspec(dllexport) __type
+#define PR_EXPORT_DATA(__type) extern _declspec(dllexport) __type
+#define PR_IMPORT(__type) extern _declspec(dllexport) __type
+#define PR_IMPORT_DATA(__type) extern _declspec(dllexport) __type
+
 #define PR_EXTERN(__type) extern __declspec(dllexport) __type
 #define PR_IMPLEMENT(__type) __declspec(dllexport) __type
 #define PR_EXTERN_DATA(__type) extern __declspec(dllexport) __type
@@ -92,6 +103,11 @@
 #define PR_CALLBACK_DECL        __cdecl
 
 #if defined(_WINDLL)
+#define PR_EXPORT(__type) extern __type _cdecl _export _loadds
+#define PR_IMPORT(__type) extern __type _cdecl _export _loadds
+#define PR_EXPORT_DATA(__type) extern __type _export
+#define PR_IMPORT_DATA(__type) extern __type _export
+
 #define PR_EXTERN(__type) extern __type _cdecl _export _loadds
 #define PR_IMPLEMENT(__type) __type _cdecl _export _loadds
 #define PR_EXTERN_DATA(__type) extern __type _export
@@ -101,6 +117,11 @@
 #define PR_STATIC_CALLBACK(__x) static __x PR_CALLBACK
 
 #else /* this must be .EXE */
+#define PR_EXPORT(__type) extern __type _cdecl _export
+#define PR_IMPORT(__type) extern __type _cdecl _export
+#define PR_EXPORT_DATA(__type) extern __type _export
+#define PR_IMPORT_DATA(__type) extern __type _export
+
 #define PR_EXTERN(__type) extern __type _cdecl _export
 #define PR_IMPLEMENT(__type) __type _cdecl _export
 #define PR_EXTERN_DATA(__type) extern __type _export
@@ -111,6 +132,12 @@
 #endif /* _WINDLL */
 
 #elif defined(XP_MAC)
+
+#define PR_EXPORT(__type) extern _declspec(export) __type
+#define PR_EXPORT_DATA(__type) extern _declspec(export) __type
+#define PR_IMPORT(__type) extern _declspec(export) __type
+#define PR_IMPORT_DATA(__type) extern _declspec(export) __type
+
 #define PR_EXTERN(__type) extern __declspec(export) __type
 #define PR_IMPLEMENT(__type) __declspec(export) __type
 #define PR_EXTERN_DATA(__type) extern __declspec(export) __type
@@ -121,6 +148,12 @@
 #define PR_STATIC_CALLBACK(__x) static __x
 
 #elif defined(XP_OS2) 
+
+#define PR_EXPORT(__type) extern __type
+#define PR_EXPORT_DATA(__type) extern __type
+#define PR_IMPORT(__type) extern __type
+#define PR_IMPORT_DATA(__type) extern __type
+
 #define PR_EXTERN(__type) extern __type
 #define PR_IMPLEMENT(__type) __type
 #define PR_EXTERN_DATA(__type) extern __type
@@ -134,6 +167,12 @@
 #endif
 
 #else /* Unix */
+
+#define PR_EXPORT(__type) extern __type
+#define PR_EXPORT_DATA(__type) extern __type
+#define PR_IMPORT(__type) extern __type
+#define PR_IMPORT_DATA(__type) extern __type
+
 #define PR_EXTERN(__type) extern __type
 #define PR_IMPLEMENT(__type) __type
 #define PR_EXTERN_DATA(__type) extern __type
@@ -144,6 +183,14 @@
 
 #endif
 
+#if defined(_NSPR_BUILD_)
+#define NSPR_API(__type) PR_EXPORT(__type)
+#define NSPR_DATA_API(__type) PR_EXPORT_DATA(__type)
+#else
+#define NSPR_API(__type) PR_IMPORT(__type)
+#define NSPR_DATA_API(__type) PR_IMPORT_DATA(__type)
+#endif
+
 /***********************************************************************
 ** MACROS:      PR_BEGIN_MACRO
 **              PR_END_MACRO
diff --git a/nsprpub/pr/src/Makefile b/nsprpub/pr/src/Makefile
index 8f7c4416ee9c..c064e7ad6623 100644
--- a/nsprpub/pr/src/Makefile
+++ b/nsprpub/pr/src/Makefile
@@ -364,6 +364,8 @@ else
 	SUF = LL
 endif
 
+DEFINES     += -D_NSPR_BUILD_
+
 $(TINC):
 	@$(MAKE_OBJDIR)
 	@$(ECHO) '#define _BUILD_STRING "$(SH_DATE)"' > $(TINC)
diff --git a/nsprpub/pr/src/bthreads/Makefile b/nsprpub/pr/src/bthreads/Makefile
index 4f20d205027b..1bddbdc070de 100644
--- a/nsprpub/pr/src/bthreads/Makefile
+++ b/nsprpub/pr/src/bthreads/Makefile
@@ -25,6 +25,8 @@ INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include
 
 include $(MOD_DEPTH)/config/rules.mk
 
+DEFINES     += -D_NSPR_BUILD_
+
 export:: $(TARGETS)
 
 install:: export
diff --git a/nsprpub/pr/src/cplus/Makefile b/nsprpub/pr/src/cplus/Makefile
index 48312806bba4..35c9df7bbb61 100644
--- a/nsprpub/pr/src/cplus/Makefile
+++ b/nsprpub/pr/src/cplus/Makefile
@@ -40,6 +40,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 HEADERS = *.h
diff --git a/nsprpub/pr/src/io/Makefile b/nsprpub/pr/src/io/Makefile
index 47bd41b72e10..692976e7a380 100644
--- a/nsprpub/pr/src/io/Makefile
+++ b/nsprpub/pr/src/io/Makefile
@@ -59,6 +59,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/linking/Makefile b/nsprpub/pr/src/linking/Makefile
index 4672384a98bc..26baca791d2b 100644
--- a/nsprpub/pr/src/linking/Makefile
+++ b/nsprpub/pr/src/linking/Makefile
@@ -36,6 +36,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/malloc/Makefile b/nsprpub/pr/src/malloc/Makefile
index 947c327e2a3a..1e85dc5c2932 100644
--- a/nsprpub/pr/src/malloc/Makefile
+++ b/nsprpub/pr/src/malloc/Makefile
@@ -32,6 +32,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 CSRCS = prmalloc.c prmem.c
 
 include $(MOD_DEPTH)/config/rules.mk
diff --git a/nsprpub/pr/src/md/Makefile b/nsprpub/pr/src/md/Makefile
index 780fcba2dbeb..765d0f620599 100644
--- a/nsprpub/pr/src/md/Makefile
+++ b/nsprpub/pr/src/md/Makefile
@@ -50,6 +50,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/md/beos/Makefile b/nsprpub/pr/src/md/beos/Makefile
index e286be58d915..ce21aecec4f5 100644
--- a/nsprpub/pr/src/md/beos/Makefile
+++ b/nsprpub/pr/src/md/beos/Makefile
@@ -21,6 +21,8 @@ TARGETS		= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/md/os2/Makefile b/nsprpub/pr/src/md/os2/Makefile
index 77689e247abe..6e9390dc2c2e 100644
--- a/nsprpub/pr/src/md/os2/Makefile
+++ b/nsprpub/pr/src/md/os2/Makefile
@@ -40,6 +40,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/md/unix/Makefile b/nsprpub/pr/src/md/unix/Makefile
index f09002817e66..de8baadd25a7 100644
--- a/nsprpub/pr/src/md/unix/Makefile
+++ b/nsprpub/pr/src/md/unix/Makefile
@@ -280,6 +280,8 @@ endif
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/md/windows/Makefile b/nsprpub/pr/src/md/windows/Makefile
index dcce31d166b8..78a6527ff282 100644
--- a/nsprpub/pr/src/md/windows/Makefile
+++ b/nsprpub/pr/src/md/windows/Makefile
@@ -76,6 +76,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/memory/Makefile b/nsprpub/pr/src/memory/Makefile
index dde16b2de66a..257623089ed7 100644
--- a/nsprpub/pr/src/memory/Makefile
+++ b/nsprpub/pr/src/memory/Makefile
@@ -34,6 +34,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/misc/Makefile b/nsprpub/pr/src/misc/Makefile
index fd78f1175d89..fd3985c252a3 100644
--- a/nsprpub/pr/src/misc/Makefile
+++ b/nsprpub/pr/src/misc/Makefile
@@ -61,6 +61,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 RELEASE_BINS = compile-et.pl prerr.properties
 
 include $(MOD_DEPTH)/config/rules.mk
diff --git a/nsprpub/pr/src/pthreads/Makefile b/nsprpub/pr/src/pthreads/Makefile
index adae2a789c66..d2700995de9f 100644
--- a/nsprpub/pr/src/pthreads/Makefile
+++ b/nsprpub/pr/src/pthreads/Makefile
@@ -39,6 +39,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/threads/Makefile b/nsprpub/pr/src/threads/Makefile
index d9ce2ca29a2e..0294ca572b15 100644
--- a/nsprpub/pr/src/threads/Makefile
+++ b/nsprpub/pr/src/threads/Makefile
@@ -68,6 +68,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)
diff --git a/nsprpub/pr/src/threads/combined/Makefile b/nsprpub/pr/src/threads/combined/Makefile
index 19e676d4aae5..f45fdecbab8f 100644
--- a/nsprpub/pr/src/threads/combined/Makefile
+++ b/nsprpub/pr/src/threads/combined/Makefile
@@ -45,6 +45,8 @@ TARGETS	= $(OBJS)
 
 INCLUDES = -I$(DIST)/include -I$(MOD_DEPTH)/pr/include -I$(MOD_DEPTH)/pr/include/private
 
+DEFINES     += -D_NSPR_BUILD_
+
 include $(MOD_DEPTH)/config/rules.mk
 
 export:: $(TARGETS)