diff --git a/Makefile b/Makefile
index 2a15469..6c9d118 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,11 @@ INSTALL = install
 #
 # Define NEEDS_LIBICONV if linking with libc is not enough (eg. Darwin).
 #
+# Define NO_C99_FORMAT if your formatted IO functions (printf/scanf et.al.)
+# do not support the 'size specifiers' introduced by C99, namely ll, hh,
+# j, z, t. (representing long long int, char, intmax_t, size_t, ptrdiff_t).
+# some C compilers supported these specifiers prior to C99 as an extension.
+#
 
 #-include config.mak
 
@@ -127,6 +132,9 @@ endif
 ifdef NO_STRCASESTR
 	CFLAGS += -DNO_STRCASESTR
 endif
+ifdef NO_C99_FORMAT
+	CFLAGS += -DNO_C99_FORMAT
+endif
 ifdef NO_OPENSSL
 	CFLAGS += -DNO_OPENSSL
 	GIT_OPTIONS += NO_OPENSSL=1
diff --git a/cgit.c b/cgit.c
index d6146e2..3b3f8d9 100644
--- a/cgit.c
+++ b/cgit.c
@@ -610,7 +610,7 @@ static void process_cached_repolist(const char *path)
 	hash = hash_str(path);
 	if (ctx.cfg.project_list)
 		hash += hash_str(ctx.cfg.project_list);
-	cached_rc = xstrdup(fmt("%s/rc-%8x", ctx.cfg.cache_root, hash));
+	cached_rc = xstrdup(fmt("%s/rc-%8lx", ctx.cfg.cache_root, hash));
 
 	if (stat(cached_rc, &st)) {
 		/* Nothing is cached, we need to scan without forking. And
diff --git a/ui-diff.c b/ui-diff.c
index 0dcabe9..7ff7e46 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -92,7 +92,7 @@ static void print_fileinfo(struct fileinfo *info)
 		      info->old_path);
 	html("</td><td class='right'>");
 	if (info->binary) {
-		htmlf("bin</td><td class='graph'>%d -> %d bytes",
+		htmlf("bin</td><td class='graph'>%ld -> %ld bytes",
 		      info->old_size, info->new_size);
 		return;
 	}
diff --git a/ui-log.c b/ui-log.c
index 0536b23..41b5225 100644
--- a/ui-log.c
+++ b/ui-log.c
@@ -228,8 +228,7 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
 		commit->parents = NULL;
 	}
 	if (pager) {
-		htmlf("</table><div class='pager'>",
-		     columns);
+		html("</table><div class='pager'>");
 		if (ofs > 0) {
 			cgit_log_link("[prev]", NULL, NULL, ctx.qry.head,
 				      ctx.qry.sha1, ctx.qry.vpath,
diff --git a/ui-stats.c b/ui-stats.c
index 50c2540..946a6ea 100644
--- a/ui-stats.c
+++ b/ui-stats.c
@@ -5,6 +5,12 @@
 #include "ui-shared.h"
 #include "ui-stats.h"
 
+#ifdef NO_C99_FORMAT
+#define SZ_FMT "%u"
+#else
+#define SZ_FMT "%zu"
+#endif
+
 #define MONTHS 6
 
 struct authorstat {
@@ -283,10 +289,10 @@ void print_combined_authorrow(struct string_list *authors, int from, int to,
 			if (date)
 				subtotal += (size_t)date->util;
 		}
-		htmlf("<td class='%s'>%d</td>", centerclass, subtotal);
+		htmlf("<td class='%s'>%ld</td>", centerclass, subtotal);
 		total += subtotal;
 	}
-	htmlf("<td class='%s'>%d</td></tr>", rightclass, total);
+	htmlf("<td class='%s'>%ld</td></tr>", rightclass, total);
 }
 
 void print_authors(struct string_list *authors, int top,
@@ -335,16 +341,16 @@ void print_authors(struct string_list *authors, int top,
 			if (!date)
 				html("<td>0</td>");
 			else {
-				htmlf("<td>%d</td>", date->util);
+				htmlf("<td>"SZ_FMT"</td>", (size_t)date->util);
 				total += (size_t)date->util;
 			}
 		}
-		htmlf("<td class='sum'>%d</td></tr>", total);
+		htmlf("<td class='sum'>%ld</td></tr>", total);
 	}
 
 	if (top < authors->nr)
 		print_combined_authorrow(authors, top, authors->nr - 1,
-			"Others (%d)", "left", "", "sum", period);
+			"Others (%ld)", "left", "", "sum", period);
 
 	print_combined_authorrow(authors, 0, authors->nr - 1, "Total",
 		"total", "sum", "sum", period);
@@ -367,7 +373,7 @@ void cgit_show_stats(struct cgit_context *ctx)
 
 	i = cgit_find_stats_period(code, &period);
 	if (!i) {
-		cgit_print_error(fmt("Unknown statistics type: %c", code));
+		cgit_print_error(fmt("Unknown statistics type: %c", code[0]));
 		return;
 	}
 	if (i > ctx->repo->max_stats) {
diff --git a/ui-tree.c b/ui-tree.c
index 75ec9cb..0cdbf6d 100644
--- a/ui-tree.c
+++ b/ui-tree.c
@@ -67,7 +67,7 @@ static void print_binary_buffer(char *buf, unsigned long size)
 	html("<table summary='blob content' class='bin-blob'>\n");
 	html("<tr><th>ofs</th><th>hex dump</th><th>ascii</th></tr>");
 	for (ofs = 0; ofs < size; ofs += ROWLEN, buf += ROWLEN) {
-		htmlf("<tr><td class='right'>%04x</td><td class='hex'>", ofs);
+		htmlf("<tr><td class='right'>%04lx</td><td class='hex'>", ofs);
 		for (idx = 0; idx < ROWLEN && ofs + idx < size; idx++)
 			htmlf("%*s%02x",
 			      idx == 16 ? 4 : 1, "",
@@ -108,7 +108,7 @@ static void print_object(const unsigned char *sha1, char *path, const char *base
 	html(")\n");
 
 	if (ctx.cfg.max_blob_size && size / 1024 > ctx.cfg.max_blob_size) {
-		htmlf("<div class='error'>blob size (%dKB) exceeds display size limit (%dKB).</div>",
+		htmlf("<div class='error'>blob size (%ldKB) exceeds display size limit (%dKB).</div>",
 				size / 1024, ctx.cfg.max_blob_size);
 		return;
 	}