--- a/gencode.c
+++ b/gencode.c
@@ -543,20 +543,6 @@ pcap_compile_nopcap(int snaplen_arg, int
 }
 
 /*
- * Clean up a "struct bpf_program" by freeing all the memory allocated
- * in it.
- */
-void
-pcap_freecode(struct bpf_program *program)
-{
-	program->bf_len = 0;
-	if (program->bf_insns != NULL) {
-		free((char *)program->bf_insns);
-		program->bf_insns = NULL;
-	}
-}
-
-/*
  * Backpatch the blocks in 'list' to 'target'.  The 'sense' field indicates
  * which of the jt and jf fields has been resolved and which is a pointer
  * back to another unresolved block (or nil).  At least one of the fields
--- a/pcap.c
+++ b/pcap.c
@@ -1087,6 +1087,59 @@ static const u_char charmap[] = {
 	(u_char)'\374', (u_char)'\375', (u_char)'\376', (u_char)'\377',
 };
 
+/*
+ * Clean up a "struct bpf_program" by freeing all the memory allocated
+ * in it.
+ */
+void
+pcap_freecode(struct bpf_program *program)
+{
+	program->bf_len = 0;
+	if (program->bf_insns != NULL) {
+		free((char *)program->bf_insns);
+		program->bf_insns = NULL;
+	}
+}
+
+/*
+ * Make a copy of a BPF program and put it in the "fcode" member of
+ * a "pcap_t".
+ *
+ * If we fail to allocate memory for the copy, fill in the "errbuf"
+ * member of the "pcap_t" with an error message, and return -1;
+ * otherwise, return 0.
+ */
+int
+install_bpf_program(pcap_t *p, struct bpf_program *fp)
+{
+	size_t prog_size;
+
+	/*
+	 * Validate the program.
+	 */
+	if (!bpf_validate(fp->bf_insns, fp->bf_len)) {
+		snprintf(p->errbuf, sizeof(p->errbuf),
+			"BPF program is not valid");
+		return (-1);
+	}
+
+	/*
+	 * Free up any already installed program.
+	 */
+	pcap_freecode(&p->fcode);
+
+	prog_size = sizeof(*fp->bf_insns) * fp->bf_len;
+	p->fcode.bf_len = fp->bf_len;
+	p->fcode.bf_insns = (struct bpf_insn *)malloc(prog_size);
+	if (p->fcode.bf_insns == NULL) {
+		snprintf(p->errbuf, sizeof(p->errbuf),
+			 "malloc: %s", pcap_strerror(errno));
+		return (-1);
+	}
+	memcpy(p->fcode.bf_insns, fp->bf_insns, prog_size);
+	return (0);
+}
+
 int
 pcap_strcasecmp(const char *s1, const char *s2)
 {
--- a/optimize.c
+++ b/optimize.c
@@ -2203,45 +2203,6 @@ icode_to_fcode(struct block *root, u_int
 	return fp;
 }
 
-/*
- * Make a copy of a BPF program and put it in the "fcode" member of
- * a "pcap_t".
- *
- * If we fail to allocate memory for the copy, fill in the "errbuf"
- * member of the "pcap_t" with an error message, and return -1;
- * otherwise, return 0.
- */
-int
-install_bpf_program(pcap_t *p, struct bpf_program *fp)
-{
-	size_t prog_size;
-
-	/*
-	 * Validate the program.
-	 */
-	if (!bpf_validate(fp->bf_insns, fp->bf_len)) {
-		snprintf(p->errbuf, sizeof(p->errbuf),
-			"BPF program is not valid");
-		return (-1);
-	}
-
-	/*
-	 * Free up any already installed program.
-	 */
-	pcap_freecode(&p->fcode);
-
-	prog_size = sizeof(*fp->bf_insns) * fp->bf_len;
-	p->fcode.bf_len = fp->bf_len;
-	p->fcode.bf_insns = (struct bpf_insn *)malloc(prog_size);
-	if (p->fcode.bf_insns == NULL) {
-		snprintf(p->errbuf, sizeof(p->errbuf),
-			 "malloc: %s", pcap_strerror(errno));
-		return (-1);
-	}
-	memcpy(p->fcode.bf_insns, fp->bf_insns, prog_size);
-	return (0);
-}
-
 #ifdef BDEBUG
 static void
 dot_dump_node(struct block *block, struct bpf_program *prog, FILE *out)
--- a/pcap-common.c
+++ b/pcap-common.c
@@ -1372,14 +1372,23 @@ swap_pseudo_headers(int linktype, struct
 	switch (linktype) {
 
 	case DLT_USB_LINUX:
+#ifndef PCAP_SUPPORT_USB
+		return;
+#endif
 		swap_linux_usb_header(hdr, data, 0);
 		break;
 
 	case DLT_USB_LINUX_MMAPPED:
+#ifndef PCAP_SUPPORT_USB
+		return;
+#endif
 		swap_linux_usb_header(hdr, data, 1);
 		break;
 
 	case DLT_NFLOG:
+#ifndef PCAP_SUPPORT_NETFILTER
+		return;
+#endif
 		swap_nflog_header(hdr, data);
 		break;
 	}