Documentation updates for release 15.8

Author: smuehlst

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Release History
 
+## [v15.8](https://github.com/smuehlst/circle-stdlib/releases/tag/v15.8)
+
+* Synced with [Circle Step 44.2](https://github.com/rsta2/circle/releases/tag/Step44.2).
+* Aligned toolchain version with Circle (gcc 10.3-2021.07).
+* Updated Mbed TLS to version 2.16.11.
+
 ## [v15.7](https://github.com/smuehlst/circle-stdlib/releases/tag/v15.7)
 
 * Synced with [Circle Step 44](https://github.com/rsta2/circle/releases/tag/Step44).

README.md

@@ -23,13 +23,13 @@ Circle (call configure with `--opt-tls`, see also the
 A toolchain from [Arm Developer GNU-A Downloads](https://developer.arm.com/open-source/gnu-toolchain/gnu-a/downloads):
 
 * Hosted on Intel Linux or Windows 10 Subsystem for Linux (WSL) (build is tested with [GitHub Action](https://github.com/smuehlst/circle-stdlib/actions)):
-  * gcc 10.2-2020.11
-    * [AArch32 bare-metal target (arm-none-eabi)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.2-2020.11/binrel/gcc-arm-10.2-2020.11-x86_64-arm-none-eabi.tar.xz)
-    * [AArch64 ELF bare-metal target (aarch64-none-elf)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.2-2020.11/binrel/gcc-arm-10.2-2020.11-x86_64-aarch64-none-elf.tar.xz)
+  * gcc 10.3-2021.07
+    * [AArch32 bare-metal target (arm-none-eabi)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.3-2021.07/binrel/gcc-arm-10.3-2021.07-x86_64-arm-none-eabi.tar.xz)
+    * [AArch64 ELF bare-metal target (aarch64-none-elf)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.3-2021.07/binrel/gcc-arm-10.3-2021.07-x86_64-aarch64-none-elf.tar.xz)
 * Hosted on 64-bit Linux on Raspberry Pi (not tested, but reported to work):
-  * gcc 10.2-2020.11
-    * [AArch32 bare-metal target (arm-none-eabi)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.2-2020.11/binrel/gcc-arm-10.2-2020.11-aarch64-arm-none-eabi.tar.xz)
-    * [AArch64 ELF bare-metal target (aarch64-none-elf)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.2-2020.11/binrel/gcc-arm-10.2-2020.11-x86_64-aarch64-none-elf.tar.xz)
+  * gcc 10.3-2021.07
+    * [AArch32 bare-metal target (arm-none-eabi)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.3-2021.07/binrel/gcc-arm-10.3-2021.07-aarch64-arm-none-eabi.tar.xz)
+    * [AArch64 ELF bare-metal target (aarch64-none-elf)](https://developer.arm.com/-/media/Files/downloads/gnu-a/10.3-2021.07/binrel/gcc-arm-10.3-2021.07-aarch64-aarch64-none-elf.tar.xz)
 
 ### Building the Libraries