VMS doesn't support includes of paths very well.

crypto/crypto-lib.com

@@ -1016,7 +1016,7 @@ $     IF ARCH.EQS."VAX" .AND. F$TRNLNM("DECC$CC_DEFAULT").NES."/DECC" -
 	 THEN CC = "CC/DECC"
 $     CC = CC + "/''CC_OPTIMIZE'/''DEBUGGER'/STANDARD=ANSI89" + -
            "/NOLIST/PREFIX=ALL" + -
-	   "/INCLUDE=(SYS$DISK:[],SYS$DISK:[-],SYS$DISK:[.ENGINE.VENDOR_DEFNS],SYS$DISK:[.EVP])" + -
+	   "/INCLUDE=(SYS$DISK:[],SYS$DISK:[-],SYS$DISK:[.ENGINE.VENDOR_DEFNS],SYS$DISK:[.EVP],SYS$DISK:[.ASN1])" + -
 	   CCEXTRAFLAGS
 $!
 $!    Define The Linker Options File Name.
@@ -1050,7 +1050,7 @@ $	EXIT
 $     ENDIF
 $     IF F$TRNLNM("DECC$CC_DEFAULT").EQS."/DECC" THEN CC = "CC/VAXC"
 $     CC = CC + "/''CC_OPTIMIZE'/''DEBUGGER'/NOLIST" + -
-	   "/INCLUDE=(SYS$DISK:[],SYS$DISK:[-],SYS$DISK:[.ENGINE.VENDOR_DEFNS])" + -
+	   "/INCLUDE=(SYS$DISK:[],SYS$DISK:[-],SYS$DISK:[.ENGINE.VENDOR_DEFNS],SYS$DISK:[.EVP],SYS$DISK:[.ASN1])" + -
 	   CCEXTRAFLAGS
 $     CCDEFS = """VAXC""," + CCDEFS
 $!
@@ -1082,7 +1082,7 @@ $!
 $!    Use GNU C...
 $!
 $     CC = "GCC/NOCASE_HACK/''GCC_OPTIMIZE'/''DEBUGGER'/NOLIST" + -
-	   "/INCLUDE=(SYS$DISK:[],SYS$DISK:[-],SYS$DISK:[.ENGINE.VENDOR_DEFNS])" + -
+	   "/INCLUDE=(SYS$DISK:[],SYS$DISK:[-],SYS$DISK:[.ENGINE.VENDOR_DEFNS],SYS$DISK:[.EVP],SYS$DISK:[.ASN1])" + -
 	   CCEXTRAFLAGS
 $!
 $!    Define The Linker Options File Name.

crypto/evp/evp_pkey.c

@@ -69,7 +69,11 @@
 #endif
 #include <openssl/bn.h>
 
+#ifdef FLAT_INC
+#include "asn1_locl.h"
+#else
 #include "../asn1/asn1_locl.h"
+#endif
 
 /* Extract a private key from a PKCS8 structure */