From: Nevo Hed <nhed+buildroot@starry.com>
Date: Mon, 30 Aug 2021 13:28:13 -0400
Subject: [PATCH] Allow forcing of endianness for cross-compilation

Upstream-status: Invalid (upstream doesn't support cross-compilation)
See https://trac.nginx.org/nginx/ticket/2240

Signed-off-by: Nevo Hed <nhed+buildroot@starry.com>
---
 auto/endianness | 61 +++++++++++++++++++++++++++++++++++++--------------------
 auto/options    |  6 ++++++
 2 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/auto/endianness b/auto/endianness
index 1b552b6b37b8..4b2a3cd75bcc 100644
--- a/auto/endianness
+++ b/auto/endianness
@@ -26,25 +26,44 @@ int main(void) {
 
 END
 
-ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-          -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"
-
-eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
-
-if [ -x $NGX_AUTOTEST ]; then
-    if $NGX_AUTOTEST >/dev/null 2>&1; then
-        echo " little endian"
+case "${NGX_FORCE_ENDIANNESS}" in
+    little)
+        echo " little endian (forced)"
         have=NGX_HAVE_LITTLE_ENDIAN . auto/have
-    else
-        echo " big endian"
-    fi
-
-    rm -rf $NGX_AUTOTEST*
-
-else
-    rm -rf $NGX_AUTOTEST*
-
-    echo
-    echo "$0: error: cannot detect system byte ordering"
-    exit 1
-fi
+    ;;
+
+    big)
+        echo " big endian (forced)"
+    ;;
+
+    "")
+        ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
+                  -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"
+
+        eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
+
+        if [ -x $NGX_AUTOTEST ]; then
+            if $NGX_AUTOTEST >/dev/null 2>&1; then
+                echo " little endian"
+                have=NGX_HAVE_LITTLE_ENDIAN . auto/have
+            else
+                echo " big endian"
+            fi
+
+            rm -rf $NGX_AUTOTEST*
+
+        else
+            rm -rf $NGX_AUTOTEST*
+
+            echo
+            echo "$0: error: cannot detect system byte ordering"
+            exit 1
+        fi
+    ;;
+
+    *)
+        echo
+        echo "$0: error: invalid \"--force-endianness=${NGX_FORCE_ENDIANNESS}\""
+        exit 1
+    ;;
+esac
diff --git a/auto/options b/auto/options
index 48f3a1a4251b..7f4163d3449a 100644
--- a/auto/options
+++ b/auto/options
@@ -17,6 +17,8 @@ NGX_USER=
 NGX_GROUP=
 NGX_BUILD=
 
+NGX_FORCE_ENDIANNESS=
+
 CC=${CC:-cc}
 CPP=
 NGX_OBJS=objs
@@ -197,6 +199,8 @@ do
         --user=*)                        NGX_USER="$value"          ;;
         --group=*)                       NGX_GROUP="$value"         ;;
 
+        --force-endianness=*)            NGX_FORCE_ENDIANNESS="$value" ;;
+
         --crossbuild=*)                  NGX_PLATFORM="$value"      ;;
 
         --build=*)                       NGX_BUILD="$value"         ;;
@@ -434,6 +438,8 @@ cat << END
   --build=NAME                       set build name
   --builddir=DIR                     set build directory
 
+  --force-endianness=<big>|<little>  force endianness
+
   --with-select_module               enable select module
   --without-select_module            disable select module
   --with-poll_module                 enable poll module