Merge bitcoin/bitcoin#27682: build: Bump minimum supported Clang to clang-10

fa199ee614 ci: Drop NO_WERROR=1 for clang-10 build (MarcoFalke)
fad2c200f4 build: Bump minimum Clang to clang-10 (MarcoFalke)
fad7cfee8d doc: Remove outdated CentOS comment (MarcoFalke)

Pull request description:

  It doesn't make sense to support a minimum clang version that is difficult to install on all supported operating systems, which generally ship a later version:

  * Ubuntu Focal 20.04: https://packages.ubuntu.com/focal/clang-10 and https://packages.ubuntu.com/focal/clang-12
  * Debian Bullseye: https://packages.debian.org/bullseye/clang-13
  * CentOS 8 Stream: All Clang versions from 11.0 to 15.0

  Also, it allows to drop build code, which means it won't waste review when rolling over into cmake (`cmake/module/CheckStdFilesystem.cmake`).

ACKs for top commit:
  hebasto:
    ACK fa199ee614
  fanquake:
    ACK fa199ee614

Tree-SHA512: c1a0e8f191a6db866b8be3c9d254dc3f576fa021e2eaaeb68f3354554a8b38eaa90bbf9871ff92351b715e62a6b7b98cf94eba6dc53d7c951bddb6ad49ba7716

ci/test/06_script_b.sh

@@ -52,9 +52,6 @@ fi
 
 if [ -z "$NO_DEPENDS" ]; then
   if [[ $CI_IMAGE_NAME_TAG == *centos* ]]; then
-    # CentOS has problems building the depends if the config shell is not explicitly set
-    # (i.e. for libevent a Makefile with an empty SHELL variable is generated, leading to
-    #  an error as the first command is executed)
     SHELL_OPTS="LC_ALL=en_US.UTF-8 CONFIG_SHELL=/bin/dash"
   else
     SHELL_OPTS="CONFIG_SHELL="