Support newlib retargetable locking configuration

This commit adds a patch for supporting the newlib retargetable
locking configuration in the crosstool-ng.

The patch is derived from the upstream pull request for the
retargetable locking configuration (crosstool-ng/crosstool-ng#1284)
cherry-picked on top of the newlib nano variant pull request
(crosstool-ng/crosstool-ng#1279).

The work branch for this patch is available at the following location:
stephanosio/crosstool-ng/newlib_nano_variant_with_retargetable_locking

Signed-off-by: Stephanos Ioannidis <[email protected]>

Author: stephanosio

patches/0001-Add-newlib-nano-variant-configurations.patch

@@ -1,7 +1,7 @@
 From 62f28beb597e8299a79add217281143fc6cb5ac2 Mon Sep 17 00:00:00 2001
 From: Stephanos Ioannidis <[email protected]>
 Date: Thu, 28 Nov 2019 23:32:10 +0900
-Subject: [PATCH 1/5] Add newlib nano variant configurations
+Subject: [PATCH 1/6] Add newlib nano variant configurations
 
 This commit adds the new configuration option 'LIBC_NANO_NEWLIB' for
 specifying the additional 'nano' variant of newlib to be built.

patches/0002-Support-building-newlib-nano-variant.patch

@@ -1,7 +1,7 @@
 From c7e4eafab9bd940058ce38ca0484dd897c6202c1 Mon Sep 17 00:00:00 2001
 From: Stephanos Ioannidis <[email protected]>
 Date: Fri, 29 Nov 2019 01:35:57 +0900
-Subject: [PATCH 2/5] Support building newlib nano variant
+Subject: [PATCH 2/6] Support building newlib nano variant
 
 This commit updates the newlib build script to build the additional
 newlib nano variant using the nano variant-specific build options.

patches/0003-Support-building-libstdc-nano-variant.patch

@@ -1,7 +1,7 @@
 From 3fe25cedd9b6db08dcf1d990784dc3ab89c10e86 Mon Sep 17 00:00:00 2001
 From: Stephanos Ioannidis <[email protected]>
 Date: Fri, 29 Nov 2019 20:44:21 +0900
-Subject: [PATCH 3/5] Support building libstdc++ nano variant
+Subject: [PATCH 3/6] Support building libstdc++ nano variant
 
 This commit adds the new configuration option 'CC_GCC_LIBSTDCXX_NANO'
 for specifying the additional 'nano' variant of libstdc++ to be built

patches/0004-Assume-O2-by-default-for-building-gcc-target-librari.patch

@@ -1,7 +1,7 @@
 From 6a20aad951cd79b4141842f261b68614b10088d1 Mon Sep 17 00:00:00 2001
 From: Stephanos Ioannidis <[email protected]>
 Date: Sat, 30 Nov 2019 01:42:18 +0900
-Subject: [PATCH 4/5] Assume '-O2' by default for building gcc target libraries
+Subject: [PATCH 4/6] Assume '-O2' by default for building gcc target libraries
 
 The gcc target libraries (e.g. libstdc++) are currently built without
 any optimisation flag when 'CT_CC_GCC_ENABLE_TARGET_OPTSPACE' is not

patches/0005-Allow-stripping-target-toolchain-libraries.patch

@@ -1,7 +1,7 @@
 From 6fca4742a80e26ae00c1ca947e93ed20f8845714 Mon Sep 17 00:00:00 2001
 From: Stephanos Ioannidis <[email protected]>
 Date: Fri, 29 Nov 2019 22:25:17 +0900
-Subject: [PATCH 5/5] Allow stripping target toolchain libraries
+Subject: [PATCH 5/6] Allow stripping target toolchain libraries
 
 This commit adds an option to strip the target toolchain libraries
 (e.g. libc, libstdc++) of any unneeded or debugging information.

patches/0006-Add-newlib-retargetable-locking-configuration.patch

@@ -0,0 +1,61 @@
+From 968bf7d65812bba490c4222b3d05fa94cf856472 Mon Sep 17 00:00:00 2001
+From: Stephanos Ioannidis <[email protected]>
+Date: Fri, 20 Dec 2019 11:18:46 +0900
+Subject: [PATCH 6/6] Add newlib retargetable locking configuration
+
+This commit adds support for the newlib configuration option
+'--enable-newlib-retargetable-locking'.
+
+Signed-off-by: Stephanos Ioannidis <[email protected]>
+---
+ config/libc/newlib.in        | 14 ++++++++++++++
+ scripts/build/libc/newlib.sh |  1 +
+ 2 files changed, 15 insertions(+)
+
+diff --git a/config/libc/newlib.in b/config/libc/newlib.in
+index bd193cd8..d84db70b 100644
+--- a/config/libc/newlib.in
++++ b/config/libc/newlib.in
+@@ -152,6 +152,13 @@ config LIBC_NEWLIB_MULTITHREAD
+     help
+         Enable support for multiple threads.
+ 
++config LIBC_NEWLIB_RETARGETABLE_LOCKING
++    bool
++    prompt "Enable retargetable locking"
++    help
++        Enable retargetable locking to allow the operating system to override
++        the dummy lock functions defined within the newlib.
++
+ config LIBC_NEWLIB_EXTRA_SECTIONS
+     bool
+     prompt "Place each function & data element in their own section"
+@@ -355,6 +362,13 @@ config LIBC_NANO_NEWLIB_MULTITHREAD
+     help
+         Enable support for multiple threads.
+ 
++config LIBC_NANO_NEWLIB_RETARGETABLE_LOCKING
++    bool
++    prompt "Enable retargetable locking"
++    help
++        Enable retargetable locking to allow the operating system to override
++        the dummy lock functions defined within the newlib.
++
+ config LIBC_NANO_NEWLIB_EXTRA_SECTIONS
+     bool
+     prompt "Place each function & data element in their own section"
+diff --git a/scripts/build/libc/newlib.sh b/scripts/build/libc/newlib.sh
+index ca53c7f8..299698ac 100644
+--- a/scripts/build/libc/newlib.sh
++++ b/scripts/build/libc/newlib.sh
+@@ -220,6 +220,7 @@ GLOBAL_ATEXIT:newlib-global-atexit
+ LITE_EXIT:lite-exit
+ REENT_SMALL:newlib-reent-small
+ MULTITHREAD:newlib-multithread
++RETARGETABLE_LOCKING:newlib-retargetable-locking
+ WIDE_ORIENT:newlib-wide-orient
+ UNBUF_STREAM_OPT:newlib-unbuf-stream-opt
+ ENABLE_TARGET_OPTSPACE:target-optspace
+-- 
+2.17.1
+