configure: use m4_tolower helper

This is new in autoconf-2.69 and lets us kill off some boilerplate
in our various library tests.

configure.ac

@@ -1,7 +1,7 @@
 # Process this file with autoconf to produce a configure script.
 # Configure template for gd library
 
-AC_PREREQ(2.64)
+AC_PREREQ([2.69])
 
 # We extract version numbers from src/versions.h
 define([gv],[config/getver.sh ]$1)
@@ -123,7 +123,7 @@ dnl $2 - GD feature name to track
 dnl $3 - lower case name for user
 dnl $4 - test for the feature
 dnl The test code should set gd_found_lib=yes to indicate success.
-m4_define([GD_LIB_CHECK], [dnl
+m4_define([_GD_LIB_CHECK], [dnl
   dnl Export the flag for the user to leverage.  No other logic here.
   AC_MSG_CHECKING([whether to support $3])
   AC_ARG_WITH([$3],
@@ -179,22 +179,23 @@ m4_define([GD_LIB_CHECK], [dnl
   AM_CONDITIONAL([HAVE_$1], test "$gd_found_lib" = yes)
   gd_with_$1=$gd_found_lib
 ])
+dnl Helper to avoid repeating m4_tolower() a lot.
+m4_define([GD_LIB_CHECK], [_GD_LIB_CHECK([$1], [$2], m4_tolower([$2]), [$3])])dnl
 
 dnl Helper macro for working with external libraries with pkg-config support.
-dnl GD_LIB_PKG_CHECK([SYM], [FEATURE], [name], [pkg-config module], [...fallback test...])
+dnl GD_LIB_PKG_CHECK([SYM], [FEATURE], [pkg-config module], [...fallback test...])
 dnl $1 - upper case symbol
 dnl $2 - GD feature name to track
-dnl $3 - lower case name for user
-dnl $4 - pkg-config module to look for
-dnl $5 - fallback test for the feature
+dnl $3 - pkg-config module to look for
+dnl $4 - fallback test for the feature
 m4_define([GD_LIB_PKG_CHECK], [dnl
-  GD_LIB_CHECK([$1], [$2], [$3], [dnl
-    PKG_CHECK_MODULES([$1], [$4], [gd_found_lib=yes gd_require_pkg_name="$4"], [$5])
+  GD_LIB_CHECK([$1], [$2], [dnl
+    PKG_CHECK_MODULES([$1], [$3], [gd_found_lib=yes gd_require_pkg_name="$3"], [$4])
   ])
 ])
 
 dnl Check for zlib support.
-GD_LIB_PKG_CHECK([LIBZ], [ZLIB], [zlib], [zlib], [dnl
+GD_LIB_PKG_CHECK([LIBZ], [ZLIB], [zlib], [dnl
   AC_CHECK_LIB([z], [deflate], [dnl
     AS_VAR_APPEND([LIBZ_LIBS], [" -lz"])
     gd_found_lib=yes
@@ -202,23 +203,31 @@ GD_LIB_PKG_CHECK([LIBZ], [ZLIB], [zlib], [zlib], [dnl
 ])
 
 dnl Check for libpng support.
-GD_LIB_PKG_CHECK([LIBPNG], [PNG], [png], [libpng], [
+GD_LIB_PKG_CHECK([LIBPNG], [PNG], [libpng], [
   LIBPNG_CONFIG=$gd_with_lib/bin/libpng-config
+  AC_MSG_CHECKING([for $LIBPNG_CONFIG script])
   if test -e "$LIBPNG_CONFIG"; then
     LIBPNG_CFLAGS=`$LIBPNG_CONFIG --cflags`
     LIBPNG_LIBS=`$LIBPNG_CONFIG --ldflags`
+    AC_MSG_RESULT(yes)
     gd_found_lib=yes
+  else
+    AC_MSG_RESULT(no)
   fi
 ])
 
 dnl Check for FreeType support.
 dnl NB: "9.8.3" corresponds to freetype-2.1.10.
-GD_LIB_PKG_CHECK([LIBFREETYPE], [FREETYPE], [freetype], [freetype2 >= 9.8.3], [
+GD_LIB_PKG_CHECK([LIBFREETYPE], [FREETYPE], [freetype2 >= 9.8.3], [
   FREETYPE_CONFIG=$gd_with_lib/bin/freetype-config
+  AC_MSG_CHECKING([for $FREETYPE_CONFIG script])
   if test -e "$FREETYPE_CONFIG"; then
     LIBFREETYPE_CFLAGS=`$FREETYPE_CONFIG --cflags`
     LIBFREETYPE_LIBS=`$FREETYPE_CONFIG --libs`
+    AC_MSG_RESULT(yes)
     gd_found_lib=yes
+  else
+    AC_MSG_RESULT(no)
   fi
 ])
 if test "$gd_with_LIBFREETYPE" = "yes"; then
@@ -226,7 +235,7 @@ if test "$gd_with_LIBFREETYPE" = "yes"; then
 fi
 
 dnl Check for Raqm support.
-GD_LIB_PKG_CHECK([LIBRAQM], [RAQM], [raqm], [raqm], [
+GD_LIB_PKG_CHECK([LIBRAQM], [RAQM], [raqm], [
   AC_CHECK_LIB([raqm], [raqm_create], [dnl
     AS_VAR_APPEND([LIBRAQM_LIBS], [" -lraqm -lfreetype"])
     gd_found_lib=yes
@@ -234,7 +243,7 @@ GD_LIB_PKG_CHECK([LIBRAQM], [RAQM], [raqm], [raqm], [
 ])
 
 dnl Check for fontconfig support.
-GD_LIB_PKG_CHECK([LIBFONTCONFIG], [FONTCONFIG], [fontconfig], [fontconfig], [
+GD_LIB_PKG_CHECK([LIBFONTCONFIG], [FONTCONFIG], [fontconfig], [
   AC_CHECK_LIB([fontconfig], [FcInit], [dnl
     AS_VAR_APPEND([LIBFONTCONFIG_LIBS], [" -lfontconfig"])
     gd_found_lib=yes
@@ -242,7 +251,7 @@ GD_LIB_PKG_CHECK([LIBFONTCONFIG], [FONTCONFIG], [fontconfig], [fontconfig], [
 ])
 
 dnl Check for jpeg support.
-GD_LIB_PKG_CHECK([LIBJPEG], [JPEG], [jpeg], [libjpeg], [
+GD_LIB_PKG_CHECK([LIBJPEG], [JPEG], [libjpeg], [
   AC_CHECK_LIB([jpeg], [jpeg_set_defaults], [dnl
     AS_VAR_APPEND([LIBJPEG_LIBS], [" -ljpeg"])
     gd_found_lib=yes
@@ -250,7 +259,7 @@ GD_LIB_PKG_CHECK([LIBJPEG], [JPEG], [jpeg], [libjpeg], [
 ])
 
 dnl Check for libimagequant support.
-GD_LIB_CHECK([LIBIMAGEQUANT], [LIQ], [liq], [
+GD_LIB_CHECK([LIBIMAGEQUANT], [LIQ], [
   AC_CHECK_HEADER([libimagequant.h], [
     save_CFLAGS=$CFLAGS
     CFLAGS="$CFLAGS $OPENMP_CFLAGS"
@@ -263,7 +272,7 @@ GD_LIB_CHECK([LIBIMAGEQUANT], [LIQ], [liq], [
 ])
 
 dnl Check for xpm support.
-GD_LIB_PKG_CHECK([LIBXPM], [XPM], [xpm], [xpm], [
+GD_LIB_PKG_CHECK([LIBXPM], [XPM], [xpm], [
   AC_CHECK_LIB([Xpm], [XpmReadFileToXpmImage], [dnl
     AS_VAR_APPEND([LIBXPM_LIBS], [" -lXpm"])
     gd_found_lib=yes
@@ -271,7 +280,7 @@ GD_LIB_PKG_CHECK([LIBXPM], [XPM], [xpm], [xpm], [
 ])
 
 dnl Check for tiff support.
-GD_LIB_PKG_CHECK([LIBTIFF], [TIFF], [tiff], [libtiff-4], [
+GD_LIB_PKG_CHECK([LIBTIFF], [TIFF], [libtiff-4], [
   AC_CHECK_LIB([tiff], [TIFFClientOpen], [dnl
     AS_VAR_APPEND([LIBTIFF_LIBS], [" -ltiff"])
     gd_found_lib=yes
@@ -279,7 +288,7 @@ GD_LIB_PKG_CHECK([LIBTIFF], [TIFF], [tiff], [libtiff-4], [
 ])
 
 dnl Check for webp support.
-GD_LIB_PKG_CHECK([LIBWEBP], [WEBP], [webp], [libwebp >= 0.2.0], [
+GD_LIB_PKG_CHECK([LIBWEBP], [WEBP], [libwebp >= 0.2.0], [
   AC_CHECK_LIB([webp], [WebPGetInfo], [dnl
     AS_VAR_APPEND([LIBWEBP_LIBS], [" -lwebp"])
     gd_found_lib=yes
@@ -287,14 +296,14 @@ GD_LIB_PKG_CHECK([LIBWEBP], [WEBP], [webp], [libwebp >= 0.2.0], [
 ])
 
 dnl Check for heif support.
-GD_LIB_PKG_CHECK([LIBHEIF], [HEIF], [heif], [libheif >= 1.7.0], [
+GD_LIB_PKG_CHECK([LIBHEIF], [HEIF], [libheif >= 1.7.0], [
   AC_CHECK_LIB([heif], [heif_get_version], [dnl
     AS_VAR_APPEND([LIBHEIF_LIBS], [" -lheif"])
   ])
 ])
 
 dnl Check for avif support.
-GD_LIB_PKG_CHECK([LIBAVIF], [AVIF], [avif], [libavif >= 0.8.2], [
+GD_LIB_PKG_CHECK([LIBAVIF], [AVIF], [libavif >= 0.8.2], [
   AC_CHECK_LIB([avif], [avifVersion], [dnl
     AS_VAR_APPEND([LIBAVIF_LIBS], [" -lavif"])
     gd_found_lib=yes

src/gd_nnquant.c

@@ -112,12 +112,7 @@ typedef struct {
 
 /* Initialise network in range (0,0,0,0) to (255,255,255,255) and set parameters
    ----------------------------------------------------------------------- */
-static void initnet(nnq, thepic, len, sample, colours)
-nn_quant *nnq;
-unsigned char *thepic;
-int len;
-int sample;
-int colours;
+static void initnet(nn_quant *nnq, unsigned char *thepic, int len, int sample, int colours)
 {
 	register int i;
 	register int *p;
@@ -163,9 +158,7 @@ static void unbiasnet(nn_quant *nnq)
 }
 
 /* Output colormap to unsigned char ptr in RGBA format */
-static void getcolormap(nnq, map)
-nn_quant *nnq;
-unsigned char *map;
+static void getcolormap(nn_quant *nnq, unsigned char *map)
 {
 	int i,j;
 	for(j=0; j < nnq->netsize; j++) {
@@ -232,9 +225,7 @@ static void inxbuild(nn_quant *nnq)
 
 /* Search for ABGR values 0..255 (after net is unbiased) and return colour index
 	 ---------------------------------------------------------------------------- */
-static unsigned int inxsearch(nnq, al,b,g,r)
-nn_quant *nnq;
-register int al, b, g, r;
+static unsigned int inxsearch(nn_quant *nnq, int al, int b, int g, int r)
 {
 	register int i, j, dist, a, bestd;
 	register int *p;
@@ -306,9 +297,7 @@ register int al, b, g, r;
 
 /* Search for biased ABGR values
    ---------------------------- */
-static int contest(nnq, al,b,g,r)
-nn_quant *nnq;
-register int al,b,g,r;
+static int contest(nn_quant *nnq, int al, int b, int g, int r)
 {
 	/* finds closest neuron (min dist) and updates freq */
 	/* finds best neuron (min dist-bias) and returns position */
@@ -362,9 +351,7 @@ register int al,b,g,r;
 /* Move neuron i towards biased (a,b,g,r) by factor alpha
 	 ---------------------------------------------------- */
 
-static void altersingle(nnq, alpha,i,al,b,g,r)
-nn_quant *nnq;
-register int alpha,i,al,b,g,r;
+static void altersingle(nn_quant *nnq, int alpha, int i, int al, int b, int g, int r)
 {
 	register int *n;
 
@@ -382,10 +369,7 @@ register int alpha,i,al,b,g,r;
 /* Move adjacent neurons by precomputed alpha*(1-((i-j)^2/[r]^2)) in radpower[|i-j|]
 	 --------------------------------------------------------------------------------- */
 
-static void alterneigh(nnq, rad,i,al,b,g,r)
-nn_quant *nnq;
-int rad,i;
-register int al,b,g,r;
+static void alterneigh(nn_quant *nnq, int rad, int i, int al, int b,int g, int r)
 {
 	register int j,k,lo,hi,a;
 	register int *p, *q;
@@ -429,9 +413,7 @@ register int al,b,g,r;
 /* Main Learning Loop
    ------------------ */
 
-static void learn(nnq, verbose) /* Stu: N.B. added parameter so that main() could control verbosity. */
-nn_quant *nnq;
-int verbose;
+static void learn(nn_quant *nnq, int verbose) /* Stu: N.B. added parameter so that main() could control verbosity. */
 {
 	register int i,j,al,b,g,r;
 	int radius,rad,alpha,step,delta,samplepixels;

src/gd_tiff.c

@@ -446,9 +446,7 @@ BGD_DECLARE(void) gdImageTiffCtx(gdImagePtr image, gdIOCtx *out)
 }
 
 /* Check if we are really in 8bit mode */
-static int checkColorMap(n, r, g, b)
-int n;
-uint16_t *r, *g, *b;
+static int checkColorMap(int n, uint16_t *r, uint16_t *g, uint16_t *b)
 {
 	while (n-- > 0)
 		if (*r++ >= 256 || *g++ >= 256 || *b++ >= 256)