configure: Provide a poor man's replacement for getline()

uClibc is one such library that doesn't implement getline()

Reported-by: Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

configure.ac

@@ -818,6 +818,9 @@ if test "x$debug_msg" = "x"; then
 	debug_msg=" none"
 fi
 
+AC_CONFIG_LIBOBJ_DIR(libobj)
+AC_REPLACE_FUNCS(getline)
+
 DRIVER_NAME="intel"
 AC_SUBST([DRIVER_NAME])
 AC_SUBST([moduledir])

libobj/getline.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+extern int getline(char **line, size_t *len, FILE *file);
+
+int getline(char **line, size_t *len, FILE *file)
+{
+	char *ptr, *end;
+	int c;
+
+	if (*line == NULL) {
+		errno = EINVAL;
+		if (*len == 0)
+			*line = malloc(4096);
+		if (*line == NULL)
+			return -1;
+
+		*len = 4096;
+	}
+
+	ptr = *line;
+	end = *line + *len;
+
+	while ((c = fgetc(file)) != EOF) {
+		if (ptr + 1 >= end) {
+			char *newline;
+			int offset;
+
+			newline = realloc(*line, *len + 4096);
+			if (newline == NULL)
+				return -1;
+
+			offset = ptr - *line;
+
+			*line = newline;
+			*len += 4096;
+
+			ptr = *line + offset;
+			end = *line + *len;
+		}
+
+		*ptr++ = c;
+		if (c == '\n') {
+			*ptr = '\0';
+			return ptr - *line;
+		}
+	}
+	*ptr = '\0';
+	return -1;
+}

src/sna/sna.h

@@ -1222,4 +1222,9 @@ static inline void sigtrap_put(void)
 #define RR_Rotate_All (RR_Rotate_0 | RR_Rotate_90 | RR_Rotate_180 | RR_Rotate_270)
 #define RR_Reflect_All (RR_Reflect_X | RR_Reflect_Y)
 
+#ifndef HAVE_GETLINE
+#include <stdio.h>
+extern int getline(char **line, size_t *len, FILE *file);
+#endif
+
 #endif /* _SNA_H */