meson: Rework gnu-efi detection

Moving all of the gnu-efi detection into src/boot/efi/meson.build makes
more sense than having it partially split.

And thanks to subdir_done() we can simplify the code a lot.

Fixes: #21258

meson.build

@@ -1641,39 +1641,8 @@ conf.set10('SYSTEMD_SLOW_TESTS_DEFAULT', slow_tests)
 
 #####################################################################
 
-if get_option('efi')
-        efi_arch = host_machine.cpu_family()
-
-        if efi_arch == 'x86'
-                EFI_MACHINE_TYPE_NAME = 'ia32'
-                gnu_efi_arch = 'ia32'
-        elif efi_arch == 'x86_64'
-                EFI_MACHINE_TYPE_NAME = 'x64'
-                gnu_efi_arch = 'x86_64'
-        elif efi_arch == 'arm'
-                EFI_MACHINE_TYPE_NAME = 'arm'
-                gnu_efi_arch = 'arm'
-        elif efi_arch == 'aarch64'
-                EFI_MACHINE_TYPE_NAME = 'aa64'
-                gnu_efi_arch = 'aarch64'
-        elif efi_arch == 'riscv64'
-                EFI_MACHINE_TYPE_NAME = 'riscv64'
-                gnu_efi_arch = 'riscv64'
-        else
-                EFI_MACHINE_TYPE_NAME = ''
-                gnu_efi_arch = ''
-        endif
-
-        have = true
-        conf.set_quoted('EFI_MACHINE_TYPE_NAME', EFI_MACHINE_TYPE_NAME)
-else
-        have = false
-endif
-conf.set10('ENABLE_EFI', have)
-
 subdir('src/fundamental')
 subdir('src/boot/efi')
-conf.set10('HAVE_GNU_EFI', have_gnu_efi)
 
 ############################################################
 
@@ -3887,19 +3856,14 @@ summary({
 # CPPFLAGS: ${OUR_CPPFLAGS} ${CPPFLAGS}
 # LDFLAGS:  ${OUR_LDFLAGS} ${LDFLAGS}
 
-if conf.get('ENABLE_EFI') == 1
-        summary({'EFI arch' : efi_arch},
+if conf.get('ENABLE_EFI') == 1 and conf.get('HAVE_GNU_EFI') == 1
+        summary({
+                'EFI machine type' :                efi_arch[0],
+                'EFI CC' :                          '@0@'.format(' '.join(efi_cc)),
+                'EFI lds' :                         efi_lds,
+                'EFI crt0' :                        efi_crt0,
+                'EFI include directory' :           efi_incdir},
                 section : 'Extensible Firmware Interface')
-
-        if have_gnu_efi
-                summary({
-                        'EFI machine type' :                EFI_MACHINE_TYPE_NAME,
-                        'EFI CC' :                          '@0@'.format(' '.join(efi_cc)),
-                        'EFI lds' :                         efi_lds,
-                        'EFI crt0' :                        efi_crt0,
-                        'EFI include directory' :           efi_incdir},
-                        section : 'Extensible Firmware Interface')
-        endif
 endif
 
 found = []
@@ -3947,11 +3911,11 @@ foreach tuple : [
         # components
         ['backlight'],
         ['binfmt'],
-        ['bpf-framework',         conf.get('BPF_FRAMEWORK') == 1],
+        ['bpf-framework'],
         ['coredump'],
         ['environment.d'],
         ['efi'],
-        ['gnu-efi',               have_gnu_efi],
+        ['gnu-efi'],
         ['firstboot'],
         ['hibernate'],
         ['homed'],
@@ -4008,7 +3972,7 @@ foreach tuple : [
         ['debug hashmap'],
         ['debug mmap cache'],
         ['debug siphash'],
-        ['valgrind',              conf.get('VALGRIND') == 1],
+        ['valgrind'],
         ['trace logging',         conf.get('LOG_TRACE') == 1],
         ['install tests',         install_tests],
         ['link-udev-shared',      get_option('link-udev-shared')],