Update `ax_boost_base.m4` to latest version

Upstream: https://github.com/autoconf-archive/autoconf-archive/blob/master/m4/ax_boost_base.m4
PR #17196.

configure

@@ -5741,7 +5741,7 @@ fi
     libsubdirs="lib64 libx32 lib lib64" ;; #(
   mips*64*) :
     libsubdirs="lib64 lib32 lib lib64" ;; #(
-  ppc64|powerpc64|s390x|sparc64|aarch64|ppc64le|powerpc64le|riscv64) :
+  ppc64|powerpc64|s390x|sparc64|aarch64|ppc64le|powerpc64le|riscv64|e2k) :
     libsubdirs="lib64 lib lib64" ;; #(
   *) :
     libsubdirs="lib"
@@ -5751,6 +5751,8 @@ esac
                 case ${host_cpu} in #(
   i?86) :
     multiarch_libsubdir="lib/i386-${host_os}" ;; #(
+  armv7l) :
+    multiarch_libsubdir="lib/arm-${host_os}" ;; #(
   *) :
     multiarch_libsubdir="lib/${host_cpu}-${host_os}"
      ;;

m4/ax_boost_base.m4

@@ -33,7 +33,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 47
+#serial 49
 
 # example boost program (need to pass version)
 m4_define([_AX_BOOST_BASE_PROGRAM],
@@ -114,7 +114,7 @@ AC_DEFUN([_AX_BOOST_BASE_RUNDETECT],[
     AS_CASE([${host_cpu}],
       [x86_64],[libsubdirs="lib64 libx32 lib lib64"],
       [mips*64*],[libsubdirs="lib64 lib32 lib lib64"],
-      [ppc64|powerpc64|s390x|sparc64|aarch64|ppc64le|powerpc64le|riscv64],[libsubdirs="lib64 lib lib64"],
+      [ppc64|powerpc64|s390x|sparc64|aarch64|ppc64le|powerpc64le|riscv64|e2k],[libsubdirs="lib64 lib lib64"],
       [libsubdirs="lib"]
     )
 
@@ -123,6 +123,7 @@ AC_DEFUN([_AX_BOOST_BASE_RUNDETECT],[
     dnl are almost assuredly the ones desired.
     AS_CASE([${host_cpu}],
       [i?86],[multiarch_libsubdir="lib/i386-${host_os}"],
+      [armv7l],[multiarch_libsubdir="lib/arm-${host_os}"],
       [multiarch_libsubdir="lib/${host_cpu}-${host_os}"]
     )