fix errors in printf-style format strings

There were many places where the arguments to a printf-like function did
not match the format string.  Mostly, these were a missing 'l' flag, but
there were three exceptions:

- In ui-stats.c, a size_t argument must be printed.  C99 has the "%zu"
  flag for this purpose, but not all compilers support this.  Therefore,
  we mimic what git does - use a NO_C99_FORMAT Makefile variable.

- In ui-stats.c, cgit_print_error() was called with a pointer instead of
  a character.

- In ui-log.c, the "columns" argument was never used.

Signed-off-by: Mark Lodato <lodatom@gmail.com>

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