Merge bitcoin/bitcoin#31627: depends: Fix spacing issue

8a46286 depends: Fix spacing issue (Hennadii Stepanov)

Pull request description:

  This PR resolves an issue where a missing space caused the value of the `build_AR` variable to be concatenated with the "NM=" string. This resulted in subsequent calls to `${AR}` and `${NM}` failing.

  Here is a diff for the `make -C depends print-build_id DEBUG=1` output:
  ```diff
  @@ -110,50 +110,18 @@
   CXX_STANDARD=c++20
   END CXX
   BEGIN AR
  -ar: invalid option -- '='
  -Usage: ar [emulation options] [-]{dmpqrstx}[abcDfilMNoOPsSTuvV] [--plugin <name>] [member-name] [count] archive-file file...
  -       ar -M [<mri-script]
  - commands:
  -  d            - delete file(s) from the archive
  -  m[ab]        - move file(s) in the archive
  -  p            - print file(s) found in the archive
  -  q[f]         - quick append file(s) to the archive
  -  r[ab][f][u]  - replace existing or insert new file(s) into the archive
  -  s            - act as ranlib
  -  t[O][v]      - display contents of the archive
  -  x[o]         - extract file(s) from the archive
  - command specific modifiers:
  -  [a]          - put file(s) after [member-name]
  -  [b]          - put file(s) before [member-name] (same as [i])
  -  [D]          - use zero for timestamps and uids/gids (default)
  -  [U]          - use actual timestamps and uids/gids
  -  [N]          - use instance [count] of name
  -  [f]          - truncate inserted file names
  -  [P]          - use full path names when matching
  -  [o]          - preserve original dates
  -  [O]          - display offsets of files in the archive
  -  [u]          - only replace files that are newer than current archive contents
  - generic modifiers:
  -  [c]          - do not warn if the library had to be created
  -  [s]          - create an archive index (cf. ranlib)
  -  [l <text> ]  - specify the dependencies of this library
  -  [S]          - do not build a symbol table
  -  [T]          - deprecated, use --thin instead
  -  [v]          - be verbose
  -  [V]          - display the version number
  -  @<file>      - read options from <file>
  -  --target=BFDNAME - specify the target object format as BFDNAME
  -  --output=DIRNAME - specify the output directory for extraction operations
  -  --record-libdeps=<text> - specify the dependencies of this library
  -  --thin       - make a thin archive
  - optional:
  -  --plugin <p> - load the specified plugin
  - emulation options:
  -  No emulation specific options
  -ar: supported targets: elf64-x86-64 elf32-i386 elf32-iamcu elf32-x86-64 pei-i386 pe-x86-64 pei-x86-64 elf64-little elf64-big elf32-little elf32-big elf64-littleaarch64 elf64-bigaarch64 elf32-littleaarch64 elf32-bigaarch64 elf32-littlearm elf32-bigarm pei-aarch64-little pe-aarch64-little elf64-alpha ecoff-littlealpha elf32-littlearm-fdpic elf32-bigarm-fdpic elf32-hppa-linux elf32-hppa elf64-ia64-little elf64-ia64-big pei-ia64 elf64-loongarch elf32-loongarch pei-loongarch64 elf32-m32r-linux elf32-m32rle-linux elf32-m68k elf32-tradbigmips elf32-tradlittlemips ecoff-bigmips ecoff-littlemips elf32-ntradbigmips elf64-tradbigmips elf32-ntradlittlemips elf64-tradlittlemips elf32-powerpc aixcoff-rs6000 elf32-powerpcle ppcboot elf64-powerpc elf64-powerpcle aixcoff64-rs6000 aix5coff64-rs6000 elf64-littleriscv elf32-littleriscv elf32-bigriscv elf64-bigriscv pei-riscv64-little elf32-s390 elf64-s390 elf32-sh-linux elf32-shbig-linux elf32-sh-fdpic elf32-shbig-fdpic elf32-sparc elf64-sparc pe-bigobj-x86-64 pe-i386 pdb srec symbolsrec verilog tekhex binary ihex plugin
  +GNU ar (GNU Binutils for Ubuntu) 2.42
  +Copyright (C) 2024 Free Software Foundation, Inc.
  +This program is free software; you may redistribute it under the terms of
  +the GNU General Public License version 3 or (at your option) any later version.
  +This program has absolutely no warranty.
   END AR
   BEGIN NM
  -bash: line 1: --version: command not found
  +GNU nm (GNU Binutils for Ubuntu) 2.42
  +Copyright (C) 2024 Free Software Foundation, Inc.
  +This program is free software; you may redistribute it under the terms of
  +the GNU General Public License version 3 or (at your option) any later version.
  +This program has absolutely no warranty.
   END NM
   BEGIN RANLIB
   GNU ranlib (GNU Binutils for Ubuntu) 2.42
  @@ -321,5 +289,5 @@
   NO_HARDEN=
   END NO_HARDEN
   END ALL
  -build_id=b7effe2aa166e73f6d2587fb4805ea1cca4d3f1e5c3aae2cfd59c592816b05e3
  +build_id=4173a5f75182c792550652e621f6b4a68cc27c8909385580d4efc7bc7a769f51
   make: Leaving directory '/home/hebasto/git/bitcoin/depends'
  ```

  It was accidentally introduced in bitcoin/bitcoin#29249.

ACKs for top commit:
  theuni:
    Nice catch. utACK 8a46286
  TheCharlatan:
    ACK 8a46286

Tree-SHA512: f50f3dea1f5fa545316743e61f69ad1a3b7de674604a560fd2a8d7095788cddfae4f88bee19eb2eed2e27800f94ec12bd8ee7e17d65f2a6839530d3646e5440d

depends/Makefile

@@ -141,7 +141,7 @@ include packages/packages.mk
 #     2. Before including packages/*.mk (excluding packages/packages.mk), since
 #        they rely on the build_id variables
 #
-build_id:=$(shell env CC='$(build_CC)' C_STANDARD='$(C_STANDARD)' CXX='$(build_CXX)' CXX_STANDARD='$(CXX_STANDARD)' AR='$(build_AR) 'NM='$(build_NM)' RANLIB='$(build_RANLIB)' STRIP='$(build_STRIP)' SHA256SUM='$(build_SHA256SUM)' DEBUG='$(DEBUG)' LTO='$(LTO)' NO_HARDEN='$(NO_HARDEN)' ./gen_id '$(BUILD_ID_SALT)' 'GUIX_ENVIRONMENT=$(realpath $(GUIX_ENVIRONMENT))')
+build_id:=$(shell env CC='$(build_CC)' C_STANDARD='$(C_STANDARD)' CXX='$(build_CXX)' CXX_STANDARD='$(CXX_STANDARD)' AR='$(build_AR)' NM='$(build_NM)' RANLIB='$(build_RANLIB)' STRIP='$(build_STRIP)' SHA256SUM='$(build_SHA256SUM)' DEBUG='$(DEBUG)' LTO='$(LTO)' NO_HARDEN='$(NO_HARDEN)' ./gen_id '$(BUILD_ID_SALT)' 'GUIX_ENVIRONMENT=$(realpath $(GUIX_ENVIRONMENT))')
 $(host_arch)_$(host_os)_id:=$(shell env CC='$(host_CC)' C_STANDARD='$(C_STANDARD)' CXX='$(host_CXX)' CXX_STANDARD='$(CXX_STANDARD)' AR='$(host_AR)' NM='$(host_NM)' RANLIB='$(host_RANLIB)' STRIP='$(host_STRIP)' SHA256SUM='$(build_SHA256SUM)' DEBUG='$(DEBUG)' LTO='$(LTO)' NO_HARDEN='$(NO_HARDEN)' ./gen_id '$(HOST_ID_SALT)' 'GUIX_ENVIRONMENT=$(realpath $(GUIX_ENVIRONMENT))')
 
 boost_packages_$(NO_BOOST) = $(boost_packages)