diff --git a/accel/tcg/meson.build b/accel/tcg/meson.build
index 8783edd06e..1dad6bbbfb 100644
--- a/accel/tcg/meson.build
+++ b/accel/tcg/meson.build
@@ -17,7 +17,9 @@ if get_option('plugins')
   tcg_ss.add(files('plugin-gen.c'))
 endif
 tcg_ss.add(when: libdw, if_true: files('debuginfo.c'))
-tcg_ss.add(when: 'CONFIG_LINUX', if_true: files('perf.c'))
+if targetos == 'linux'
+  tcg_ss.add(files('perf.c'))
+endif
 specific_ss.add_all(when: 'CONFIG_TCG', if_true: tcg_ss)
 
 specific_ss.add(when: ['CONFIG_SYSTEM_ONLY', 'CONFIG_TCG'], if_true: files(
diff --git a/backends/meson.build b/backends/meson.build
index 9a5cea480d..248ce4923c 100644
--- a/backends/meson.build
+++ b/backends/meson.build
@@ -12,7 +12,9 @@ system_ss.add([files(
 
 system_ss.add(when: 'CONFIG_POSIX', if_true: files('rng-random.c'))
 system_ss.add(when: 'CONFIG_POSIX', if_true: files('hostmem-file.c'))
-system_ss.add(when: 'CONFIG_LINUX', if_true: files('hostmem-memfd.c'))
+if targetos == 'linux'
+  system_ss.add(files('hostmem-memfd.c'))
+endif
 if keyutils.found()
     system_ss.add(keyutils, files('cryptodev-lkcf.c'))
 endif
diff --git a/block/meson.build b/block/meson.build
index 59ff6d380c..7faed96c1e 100644
--- a/block/meson.build
+++ b/block/meson.build
@@ -91,7 +91,9 @@ endif
 block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c', 'win32-aio.c'))
 block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit])
 block_ss.add(when: libiscsi, if_true: files('iscsi-opts.c'))
-block_ss.add(when: 'CONFIG_LINUX', if_true: files('nvme.c'))
+if targetos == 'linux'
+  block_ss.add(files('nvme.c'))
+endif
 if get_option('replication').allowed()
   block_ss.add(files('replication.c'))
 endif
diff --git a/fsdev/meson.build b/fsdev/meson.build
index 1bec065924..c76347615d 100644
--- a/fsdev/meson.build
+++ b/fsdev/meson.build
@@ -6,8 +6,9 @@ fsdev_ss.add(when: ['CONFIG_FSDEV_9P'], if_true: files(
   '9p-marshal.c',
   'qemu-fsdev.c',
 ), if_false: files('qemu-fsdev-dummy.c'))
-system_ss.add_all(when: 'CONFIG_LINUX', if_true: fsdev_ss)
-system_ss.add_all(when: 'CONFIG_DARWIN', if_true: fsdev_ss)
+if targetos in ['linux', 'darwin']
+  system_ss.add_all(fsdev_ss)
+endif
 
 if have_virtfs_proxy_helper
   executable('virtfs-proxy-helper',
diff --git a/hw/9pfs/meson.build b/hw/9pfs/meson.build
index 2944ea63c3..3eee7c268a 100644
--- a/hw/9pfs/meson.build
+++ b/hw/9pfs/meson.build
@@ -13,8 +13,11 @@ fs_ss.add(files(
   'coth.c',
   'coxattr.c',
 ))
-fs_ss.add(when: 'CONFIG_LINUX', if_true: files('9p-util-linux.c'))
-fs_ss.add(when: 'CONFIG_DARWIN', if_true: files('9p-util-darwin.c'))
+if targetos == 'darwin'
+  fs_ss.add(files('9p-util-darwin.c'))
+elif targetos == 'linux'
+  fs_ss.add(files('9p-util-linux.c'))
+endif
 fs_ss.add(when: 'CONFIG_XEN_BUS', if_true: files('xen-9p-backend.c'))
 system_ss.add_all(when: 'CONFIG_FSDEV_9P', if_true: fs_ss)
 
diff --git a/hw/display/meson.build b/hw/display/meson.build
index 344dfe3d8c..02b0044c9e 100644
--- a/hw/display/meson.build
+++ b/hw/display/meson.build
@@ -69,8 +69,11 @@ if config_all_devices.has_key('CONFIG_VIRTIO_GPU')
   virtio_gpu_ss = ss.source_set()
   virtio_gpu_ss.add(when: 'CONFIG_VIRTIO_GPU',
                     if_true: [files('virtio-gpu-base.c', 'virtio-gpu.c'), pixman])
-  virtio_gpu_ss.add(when: 'CONFIG_LINUX', if_true: files('virtio-gpu-udmabuf.c'),
-                                          if_false: files('virtio-gpu-udmabuf-stubs.c'))
+  if targetos == 'linux'
+    virtio_gpu_ss.add(files('virtio-gpu-udmabuf.c'))
+  else
+    virtio_gpu_ss.add(files('virtio-gpu-udmabuf-stubs.c'))
+  endif
   virtio_gpu_ss.add(when: 'CONFIG_VHOST_USER_GPU', if_true: files('vhost-user-gpu.c'))
   hw_display_modules += {'virtio-gpu': virtio_gpu_ss}
 
diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build
index ea44856d43..3dedcf3043 100644
--- a/hw/ppc/meson.build
+++ b/hw/ppc/meson.build
@@ -34,9 +34,11 @@ ppc_ss.add(when: ['CONFIG_PSERIES', 'CONFIG_TCG'], if_true: files(
   'spapr_softmmu.c',
 ))
 ppc_ss.add(when: 'CONFIG_SPAPR_RNG', if_true: files('spapr_rng.c'))
-ppc_ss.add(when: ['CONFIG_PSERIES', 'CONFIG_LINUX'], if_true: files(
-  'spapr_pci_vfio.c',
-))
+if targetos == 'linux'
+  ppc_ss.add(when: 'CONFIG_PSERIES', if_true: files(
+    'spapr_pci_vfio.c',
+  ))
+endif
 
 # IBM PowerNV
 ppc_ss.add(when: 'CONFIG_POWERNV', if_true: files(
diff --git a/hw/usb/meson.build b/hw/usb/meson.build
index e94149ebde..4b44db39cd 100644
--- a/hw/usb/meson.build
+++ b/hw/usb/meson.build
@@ -58,7 +58,9 @@ endif
 
 # U2F
 system_ss.add(when: 'CONFIG_USB_U2F', if_true: files('u2f.c'))
-system_ss.add(when: ['CONFIG_LINUX', 'CONFIG_USB_U2F'], if_true: [libudev, files('u2f-passthru.c')])
+if targetos == 'linux'
+  system_ss.add(when: 'CONFIG_USB_U2F', if_true: [libudev, files('u2f-passthru.c')])
+endif
 if u2f.found()
   system_ss.add(when: 'CONFIG_USB_U2F', if_true: [u2f, files('u2f-emulated.c')])
 endif
diff --git a/meson.build b/meson.build
index 7344e36382..cf224e252c 100644
--- a/meson.build
+++ b/meson.build
@@ -2888,14 +2888,6 @@ minikconf = find_program('scripts/minikconf.py')
 config_targetos = {
   (targetos == 'windows' ? 'CONFIG_WIN32' : 'CONFIG_POSIX'): 'y'
 }
-if targetos == 'darwin'
-  config_targetos += {'CONFIG_DARWIN': 'y'}
-elif targetos == 'linux'
-  config_targetos += {'CONFIG_LINUX': 'y'}
-endif
-if targetos in bsd_oses
-  config_targetos += {'CONFIG_BSD': 'y'}
-endif
 
 config_all = {}
 config_all_devices = {}
diff --git a/net/can/meson.build b/net/can/meson.build
index 45693c82c9..bdf6f8eee1 100644
--- a/net/can/meson.build
+++ b/net/can/meson.build
@@ -1,5 +1,7 @@
 can_ss = ss.source_set()
 can_ss.add(files('can_core.c', 'can_host.c'))
-can_ss.add(when: 'CONFIG_LINUX', if_true: files('can_socketcan.c'))
+if targetos == 'linux'
+  can_ss.add(files('can_socketcan.c'))
+endif
 
 system_ss.add_all(when: 'CONFIG_CAN_BUS', if_true: can_ss)
diff --git a/qga/meson.build b/qga/meson.build
index a6af614891..50edaf1c3d 100644
--- a/qga/meson.build
+++ b/qga/meson.build
@@ -72,12 +72,11 @@ qga_ss.add(when: 'CONFIG_POSIX', if_true: files(
   'commands-posix.c',
   'commands-posix-ssh.c',
 ))
-qga_ss.add(when: 'CONFIG_LINUX', if_true: files(
-  'commands-linux.c',
-))
-qga_ss.add(when: 'CONFIG_BSD', if_true: files(
-  'commands-bsd.c',
-))
+if targetos == 'linux'
+  qga_ss.add(files('commands-linux.c'))
+elif targetos in bsd_oses
+  qga_ss.add(files('commands-bsd.c'))
+endif
 qga_ss.add(when: 'CONFIG_WIN32', if_true: files(
   'channel-win32.c',
   'commands-win32.c',
diff --git a/scsi/meson.build b/scsi/meson.build
index 53f3a1f716..0ff2b3affe 100644
--- a/scsi/meson.build
+++ b/scsi/meson.build
@@ -1,4 +1,6 @@
 block_ss.add(files('utils.c'))
-block_ss.add(when: 'CONFIG_LINUX',
-             if_true: files('pr-manager.c', 'pr-manager-helper.c'),
-             if_false: files('pr-manager-stub.c'))
+if targetos == 'linux'
+  block_ss.add(files('pr-manager.c', 'pr-manager-helper.c'))
+else
+  block_ss.add(files('pr-manager-stub.c'))
+endif
diff --git a/system/meson.build b/system/meson.build
index 3a64dd89de..0632a3daa8 100644
--- a/system/meson.build
+++ b/system/meson.build
@@ -33,4 +33,6 @@ endif
 
 system_ss.add(when: seccomp, if_true: files('qemu-seccomp.c'))
 system_ss.add(when: fdt, if_true: files('device_tree.c'))
-system_ss.add(when: 'CONFIG_LINUX', if_true: files('async-teardown.c'))
+if targetos == 'linux'
+  system_ss.add('async-teardown.c')
+endif
diff --git a/ui/meson.build b/ui/meson.build
index 0ccb3387ee..8379a788a1 100644
--- a/ui/meson.build
+++ b/ui/meson.build
@@ -25,10 +25,9 @@ endif
 system_ss.add([spice_headers, files('spice-module.c')])
 system_ss.add(when: spice_protocol, if_true: files('vdagent.c'))
 
-system_ss.add(when: 'CONFIG_LINUX', if_true: files(
-  'input-linux.c',
-  'udmabuf.c',
-))
+if targetos == 'linux'
+  system_ss.add(files('input-linux.c', 'udmabuf.c'))
+endif
 system_ss.add(when: cocoa, if_true: files('cocoa.m'))
 
 vnc_ss = ss.source_set()
diff --git a/util/meson.build b/util/meson.build
index 174c133368..98dd7fa534 100644
--- a/util/meson.build
+++ b/util/meson.build
@@ -71,7 +71,9 @@ endif
 if have_system
   util_ss.add(files('crc-ccitt.c'))
   util_ss.add(when: gio, if_true: files('dbus.c'))
-  util_ss.add(when: 'CONFIG_LINUX', if_true: files('userfaultfd.c'))
+  if targetos == 'linux'
+    util_ss.add(files('userfaultfd.c'))
+  endif
 endif
 
 if have_block or have_ga
@@ -92,9 +94,6 @@ if have_block
   util_ss.add(files('iova-tree.c'))
   util_ss.add(files('iov.c', 'uri.c'))
   util_ss.add(files('nvdimm-utils.c'))
-  util_ss.add(when: 'CONFIG_LINUX', if_true: [
-    files('vhost-user-server.c'), vhost_user
-  ])
   util_ss.add(files('block-helpers.c'))
   util_ss.add(files('qemu-coroutine-sleep.c'))
   util_ss.add(files('qemu-co-shared-resource.c'))
@@ -107,8 +106,11 @@ if have_block
   else
     util_ss.add(files('filemonitor-stub.c'))
   endif
-  util_ss.add(when: 'CONFIG_LINUX', if_true: files('vfio-helpers.c'))
-  util_ss.add(when: 'CONFIG_LINUX', if_true: files('chardev_open.c'))
+  if targetos == 'linux'
+    util_ss.add(files('vhost-user-server.c'), vhost_user)
+    util_ss.add(files('vfio-helpers.c'))
+    util_ss.add(files('chardev_open.c'))
+  endif
 endif
 
 if cpu == 'aarch64'