package/libpng: add upstream patch to fix riscv64 build

Fixes:
https://autobuild.buildroot.net/results/573/573c2dc9a144da25e2d1962af09e5931a72cd8d3/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/libpng/0001-riscv-Support-only-RVV-1.0.patch

@@ -0,0 +1,246 @@
+From 7916eb7ba08e97ac97c71784e15f78e3ffcd838c Mon Sep 17 00:00:00 2001
+From: Filip Wasil <f.wasil@samsung.com>
+Date: Mon, 7 Jul 2025 11:08:35 +0200
+Subject: [PATCH] riscv: Support only RVV 1.0
+
+Reviewed-by: John Bowler <jbowler@acm.org>
+Signed-off-by: Cosmin Truta <ctruta@gmail.com>
+
+Upstream: https://github.com/pnggroup/libpng/commit/7916eb7ba08e97ac97c71784e15f78e3ffcd838c
+
+Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
+---
+ CMakeLists.txt            |  4 --
+ configure.ac              |  4 --
+ contrib/riscv-rvv/README  | 85 ---------------------------------------
+ contrib/riscv-rvv/linux.c | 36 -----------------
+ riscv/riscv_init.c        | 32 ++++-----------
+ 5 files changed, 7 insertions(+), 154 deletions(-)
+ delete mode 100644 contrib/riscv-rvv/README
+ delete mode 100644 contrib/riscv-rvv/linux.c
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index f0f3a88846..22b929ba97 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -331,10 +331,6 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
+ 
+       check_c_source_compiles("
+         #include <riscv_vector.h>
+-        #include <asm/hwcap.h>
+-        #ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+-        #error \"COMPAT_HWCAP_ISA_V is not available\"
+-        #endif
+         int main() {
+           const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+           uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+diff --git a/configure.ac b/configure.ac
+index 5b5d242c5d..bb40f6d994 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -707,10 +707,6 @@ then
+ 
+    AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+ #include <riscv_vector.h>
+-#include <asm/hwcap.h>
+-#ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+-#error "COMPAT_HWCAP_ISA_V is not available"
+-#endif
+ int main() {
+    const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+    uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+diff --git a/contrib/riscv-rvv/README b/contrib/riscv-rvv/README
+deleted file mode 100644
+index 56b7cd284b..0000000000
+--- a/contrib/riscv-rvv/README
++++ /dev/null
+@@ -1,85 +0,0 @@
+-OPERATING SYSTEM SPECIFIC RISC-V RVV DETECTION
+-----------------------------------------------
+-
+-Detection of the ability to execute RISC-V Vector on a RISC-V processor
+-requires operating system support.  (The information is not available in user
+-mode.)
+-
+-HOW TO USE THIS
+----------------
+-
+-This directory contains C code fragments that can be included in
+-riscv/riscv_init.c by setting the macro PNG_RISCV_RVV_FILE to the file name
+-in "" or <> at build time.  This setting is not recorded in pnglibconf.h and
+-can be changed simply by rebuilding riscv/riscv_init.o with the required macro
+-definition.
+-
+-For any of this code to be used the RISC-V Vector code must be enabled and run
+-time checks must be supported.  I.e.:
+-
+-#if PNG_RISCV_RVV_OPT > 0
+-#ifdef PNG_RISCV_RVV_CHECK_SUPPORTED
+-
+-This is done in a 'configure' build by passing configure the argument:
+-
+-   --enable-riscv-rvv=check
+-
+-Apart from the basic Linux implementation in contrib/riscv-rvv/linux.c this
+-code is unsupported.  That means that it is not even compiled on a regular
+-basis and may be broken in any given minor release.
+-
+-FILE FORMAT
+------------
+-
+-Each file documents its testing status as of the last time it was tested (which
+-may have been a long time ago):
+-
+-STATUS: one of:
+-   SUPPORTED: This indicates that the file is included in the regularly
+-         performed test builds and bugs are fixed when discovered.
+-   COMPILED: This indicates that the code did compile at least once.  See the
+-         more detailed description for the extent to which the result was
+-         successful.
+-   TESTED: This means the code was fully compiled into the libpng test programs
+-         and these were run at least once.
+-
+-BUG REPORTS: an email address to which to send reports of problems
+-
+-The file is a fragment of C code. It should not define any 'extern' symbols;
+-everything should be static.  It must define the function:
+-
+-static int png_have_rvv(png_structp png_ptr);
+-
+-That function must return 1 if RISC-V Vector instructions are supported, 0 if
+-not.  It must not execute png_error unless it detects a bug.  A png_error will
+-prevent the reading of the PNG and in the future, writing too.
+-
+-BUG REPORTS
+------------
+-
+-If you mail a bug report for any file that is not SUPPORTED there may only be
+-limited response.  Consider fixing it and sending a patch to fix the problem -
+-this is more likely to result in action.
+-
+-CONTRIBUTIONS
+--------------
+-
+-You may send contributions of new implementations to
+-png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+-possible.  Obviously OS dependencies are to be expected.  If you submit code you
+-must have the authors permission and it must have a license that is acceptable
+-to the current maintainer; in particular that license must permit modification
+-and redistribution.
+-
+-Please try to make the contribution a single file and give the file a clear and
+-unambiguous name that identifies the target OS.  If multiple files really are
+-required put them all in a sub-directory.
+-
+-You must also be prepared to handle bug reports from users of the code, either
+-by joining the png-mng-implement mailing list or by providing an email for the
+-"BUG REPORTS" entry or both.  Please make sure that the header of the file
+-contains the STATUS and BUG REPORTS fields as above.
+-
+-Please list the OS requirements as precisely as possible.  Ideally you should
+-also list the environment in which the code has been tested and certainly list
+-any environments where you suspect it might not work.
+diff --git a/contrib/riscv-rvv/linux.c b/contrib/riscv-rvv/linux.c
+deleted file mode 100644
+index c3a0ff808a..0000000000
+--- a/contrib/riscv-rvv/linux.c
++++ /dev/null
+@@ -1,36 +0,0 @@
+-/* contrib/riscv-rvv/linux.c
+- *
+- * Copyright (c) 2023 Google LLC
+- * Written by Dragoș Tiselice <dtiselice@google.com>, May 2023.
+- *
+- * This code is released under the libpng license.
+- * For conditions of distribution and use, see the disclaimer
+- * and license in png.h
+- *
+- * SEE contrib/riscv-rvv/README before reporting bugs
+- *
+- * STATUS: SUPPORTED
+- * BUG REPORTS: png-mng-implement@sourceforge.net
+- *
+- * png_have_rvv implemented for Linux by looking for COMPAT_HWCAP_ISA_V
+- * via hardware capabilites API.
+- *
+- * This code is strict ANSI-C and is probably moderately portable; it does
+- * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+- */
+-
+-#if defined(__linux__)
+-#include <asm/hwcap.h>
+-#include <sys/auxv.h>
+-#endif
+-
+-static int
+-png_have_rvv() {
+-#if defined(__linux__)
+-   return getauxval (AT_HWCAP) & COMPAT_HWCAP_ISA_V ? 1 : 0;
+-#else
+-#pragma message(                                                               \
+-   "warning: RISC-V Vector not supported for this platform")
+-   return 0;
+-#endif
+-}
+diff --git a/riscv/riscv_init.c b/riscv/riscv_init.c
+index 1d9982436a..11b1cb4fd6 100644
+--- a/riscv/riscv_init.c
++++ b/riscv/riscv_init.c
+@@ -12,25 +12,10 @@
+ 
+ #ifdef PNG_READ_SUPPORTED
+ 
+-#if PNG_RISCV_RVV_OPT > 0
++#if PNG_RISCV_RVV_IMPLEMENTATION > 0
+ 
+ #include <riscv_vector.h>
+ 
+-#include <signal.h>
+-
+-#ifndef PNG_RISCV_RVV_FILE
+-#  if defined(__linux__)
+-#    define PNG_RISCV_RVV_FILE "contrib/riscv-rvv/linux.c"
+-#  else
+-#    error "No support for run-time RISC-V Vector checking; use compile-time options"
+-#  endif
+-#endif
+-
+-static int png_have_rvv();
+-#ifdef PNG_RISCV_RVV_FILE
+-#  include PNG_RISCV_RVV_FILE
+-#endif
+-
+ #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+ #  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+ #endif
+@@ -38,16 +23,9 @@ static int png_have_rvv();
+ void
+ png_init_filter_functions_rvv(png_structp pp, unsigned int bpp)
+ {
++#if __riscv_v == 1000000
+    png_debug(1, "in png_init_filter_functions_rvv");
+ 
+-   static volatile sig_atomic_t no_rvv = -1; /* not checked */
+-
+-   if (no_rvv < 0)
+-      no_rvv = !png_have_rvv();
+-
+-   if (no_rvv)
+-      return;
+-
+    pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_rvv;
+ 
+    if (bpp == 3)
+@@ -62,7 +40,11 @@ png_init_filter_functions_rvv(png_structp pp, unsigned int bpp)
+       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_rvv;
+       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_rvv;
+    }
++#else
++   PNG_UNUSED(pp);
++   PNG_UNUSED(bpp);
++#endif /* __riscv_v == 1000000 */
+ }
+ 
+-#endif /* PNG_RISCV_RVV_OPT > 0 */
++#endif /* PNG_RISCV_RVV_IMPLEMENTATION > 0 */
+ #endif /* PNG_READ_SUPPORTED */

package/libpng/libpng.mk

@@ -11,6 +11,8 @@ LIBPNG_SITE = https://downloads.sourceforge.net/project/libpng/libpng$(LIBPNG_SE
 LIBPNG_LICENSE = Libpng-2.0
 LIBPNG_LICENSE_FILES = LICENSE
 LIBPNG_CPE_ID_VENDOR = libpng
+# 0001-riscv-Support-only-RVV-1.0.patch
+LIBPNG_AUTORECONF = YES
 LIBPNG_INSTALL_STAGING = YES
 LIBPNG_DEPENDENCIES = host-pkgconf zlib
 HOST_LIBPNG_DEPENDENCIES = host-pkgconf host-zlib