The initial suggestion and discussion: https://github.com/nginx/njs/pull/990
The subsequent (authored by a maintainer?) PR: https://github.com/nginx/njs/pull/993
diff --git a/auto/cc b/auto/cc
index 8a615ec4..d4b28489 100644
--- a/auto/cc
+++ b/auto/cc
@@ -64,7 +64,6 @@ case $NJS_CC_NAME in
     gcc)
         njs_define=NJS_GCC . auto/define
 
-        NJS_CFLAGS="$NJS_CFLAGS -pipe"
         NJS_CFLAGS="$NJS_CFLAGS -fPIC"
 
         # Do not export symbols except explicitly marked with NJS_EXPORT.
@@ -72,9 +71,6 @@ case $NJS_CC_NAME in
 
         # c99/gnu99 conflict with Solaris XOPEN.
         #NJS_CFLAGS="$NJS_CFLAGS -std=gnu99"
-
-        NJS_CFLAGS="$NJS_CFLAGS -O"
-        #NJS_CFLAGS="$NJS_CFLAGS -O0"
         NJS_CFLAGS="$NJS_CFLAGS -W -Wall -Wextra"
 
         #NJS_CFLAGS="$NJS_CFLAGS -Wunused-result"
@@ -94,12 +90,6 @@ case $NJS_CC_NAME in
 
         NJS_CFLAGS="$NJS_CFLAGS -Wmissing-prototypes"
 
-        # Stop on warning.
-        NJS_CFLAGS="$NJS_CFLAGS -Werror"
-
-        # Debug.
-        NJS_CFLAGS="$NJS_CFLAGS -g"
-
         if [ "$NJS_ADDRESS_SANITIZER" = "YES" ]; then
             NJS_CFLAGS="$NJS_CFLAGS -fsanitize=address"
             NJS_CFLAGS="$NJS_CFLAGS -fno-omit-frame-pointer"
@@ -109,14 +99,11 @@ case $NJS_CC_NAME in
     clang)
         njs_define=NJS_CLANG . auto/define
 
-        NJS_CFLAGS="$NJS_CFLAGS -pipe"
         NJS_CFLAGS="$NJS_CFLAGS -fPIC"
 
         # Do not export symbols except explicitly marked with NJS_EXPORT.
         NJS_CFLAGS="$NJS_CFLAGS -fvisibility=hidden"
 
-        NJS_CFLAGS="$NJS_CFLAGS -O"
-        #NJS_CFLAGS="$NJS_CFLAGS -O0"
         NJS_CFLAGS="$NJS_CFLAGS -W -Wall -Wextra"
 
         #NJS_CFLAGS="$NJS_CFLAGS -Wunused-result"
@@ -130,17 +117,6 @@ case $NJS_CC_NAME in
 
         NJS_CFLAGS="$NJS_CFLAGS -Wmissing-prototypes"
 
-        # Stop on warning.
-        NJS_CFLAGS="$NJS_CFLAGS -Werror"
-
-        # Debug.
-
-        if [ "$NJS_SYSTEM_PLATFORM" != "powerpc" ]; then
-            # "-g" flag causes the "unknown pseudo-op: `.cfi_sections'"
-            # error on PowerPC Clang.
-            NJS_CFLAGS="$NJS_CFLAGS -g"
-        fi
-
         if [ "$NJS_ADDRESS_SANITIZER" = "YES" ]; then
             NJS_CFLAGS="$NJS_CFLAGS -fsanitize=address"
             NJS_CFLAGS="$NJS_CFLAGS -fno-omit-frame-pointer"
diff --git a/auto/options b/auto/options
index 0a4dc6c7..c3399062 100644
--- a/auto/options
+++ b/auto/options
@@ -3,8 +3,8 @@
 # Copyright (C) NGINX, Inc.
 
 
-NJS_CC_OPT=${NJS_CC_OPT:--O}
-NJS_LD_OPT=${NJS_CC_OPT:--O}
+NJS_CC_OPT=
+NJS_LD_OPT=
 
 NJS_DEBUG=NO
 NJS_DEBUG_MEMORY=NO