m4: move the gawk script from m4/gen_bpf_attr_m4.sh into a separate file

As it turns out, old versions of gawk do not support -e option.

* m4/gen_bpf_attr_m4.sh: Move the gawk script ...
* m4/gen_bpf_attr_m4.awk: ... here.

Author: esyr

m4/gen_bpf_attr_m4.awk

@@ -0,0 +1,28 @@
+/^struct ([^[:space:]]+)_struct([[:space:]]+\/\* ([^[:space:]]+) \*\/)?[[:space:]]+{/ {
+	match($0, /^struct ([^[:space:]]+)_struct([[:space:]]+\/\* ([^[:space:]]+) \*\/)?[[:space:]]+{/, a)
+
+	struct_name = a[1]
+	subtype_name = a[3]
+
+	if (struct_name ~ /^BPF_/)
+		prefix = "union bpf_attr"
+	else
+		prefix = "struct " struct_name
+
+	if (subtype_name != "")
+		prefix = prefix "." subtype_name
+
+	in_struct = 1
+	next
+}
+
+/^}( ATTRIBUTE_ALIGNED\(.*\))?;/ {
+	in_struct = 0
+	next
+}
+
+(in_struct == 1) {
+	if (match($0, /^[[:space:]]+[^;\[\]]+[[:space:]]+([^[:space:]\[\];]+)(\[[^;]*\])?;$/, a)) {
+		print "\t\t" prefix "." a[1] ","
+	}
+}

m4/gen_bpf_attr_m4.sh

@@ -34,36 +34,7 @@ AC_DEFUN([st_BPF_ATTR], [dnl
 	AC_CHECK_MEMBERS(m4_normalize([
 EOF
 
-gawk -e '
-/^struct ([^[:space:]]+)_struct([[:space:]]+\/\* ([^[:space:]]+) \*\/)?[[:space:]]+{/ {
-	match($0, /^struct ([^[:space:]]+)_struct([[:space:]]+\/\* ([^[:space:]]+) \*\/)?[[:space:]]+{/, a)
-
-	struct_name = a[1]
-	subtype_name = a[3]
-
-	if (struct_name ~ /^BPF_/)
-		prefix = "union bpf_attr"
-	else
-		prefix = "struct " struct_name
-
-	if (subtype_name != "")
-		prefix = prefix "." subtype_name
-
-	in_struct = 1
-	next
-}
-
-/^}( ATTRIBUTE_ALIGNED\(.*\))?;/ {
-	in_struct = 0
-	next
-}
-
-(in_struct == 1) {
-	if (match($0, /^[[:space:]]+[^;\[\]]+[[:space:]]+([^[:space:]\[\];]+)(\[[^;]*\])?;$/, a)) {
-		print "\t\t" prefix "." a[1] ","
-	}
-}
-' < "$input" | sort -u
+gawk -f "${0%/*}"/gen_bpf_attr_m4.awk < "$input" | sort -u
 
 cat <<'EOF'
 		union bpf_attr.dummy