Add PCI device enumeration and configuration utilities

This commit introduces a new PCI library and associated tools for inspecting and modifying PCI configuration space via Linux sysfs. The following changes were made:

- Implemented `pci.c` and `pci.h` for PCI device management, including enumeration, attribute reading, and configuration space access.
- Added `setpci` command-line utility for reading and writing PCI configuration registers, with support for filtering devices by vendor, device, and slot.
- Created manual pages for `setpci` to document its usage and options.
- Developed test scripts for both `lspci` and `setpci` to ensure functionality and correctness of the new features.

These additions enhance the ability to interact with PCI devices, providing a robust framework for device management and configuration.

meson.build

@@ -104,6 +104,14 @@ xargs_src = files(
 
 xargs_inc = include_directories('src/xargs')
 
+pci_src = files(
+  'src/pci/pci.c',
+  'src/pci/lspci.c',
+  'src/pci/setpci.c',
+)
+
+pci_inc = include_directories('src/pci')
+
 gzip_defines = [
   '-DNO_BZIP2_SUPPORT',
   '-DNO_ZSTD_SUPPORT',
@@ -128,8 +136,9 @@ vx = executable('vx',
   find_src,
   getdate_gen,
   xargs_src,
+  pci_src,
   compat_src,
-  include_directories : [compat_inc, gzip_inc, grep_inc, find_inc, xargs_inc],
+  include_directories : [compat_inc, gzip_inc, grep_inc, find_inc, xargs_inc, pci_inc],
   c_args : compat_args + gzip_defines,
   dependencies : [libm, libz, liblzma, libacl],
   install : true,
@@ -137,7 +146,7 @@ vx = executable('vx',
 
 # Create symlinks for all applets pointing to the vx binary
 bindir = get_option('bindir')
-foreach name : ['patch', 'diff', 'cmp', 'diff3', 'sdiff', 'which', 'gzip', 'gunzip', 'zcat', 'uncompress', 'grep', 'egrep', 'fgrep', 'rgrep', 'find', 'xargs']
+foreach name : ['patch', 'diff', 'cmp', 'diff3', 'sdiff', 'which', 'gzip', 'gunzip', 'zcat', 'uncompress', 'grep', 'egrep', 'fgrep', 'rgrep', 'find', 'xargs', 'lspci', 'setpci']
   meson.add_install_script('sh', '-c',
     'ln -sf vx "$MESON_INSTALL_DESTDIR_PREFIX/' + bindir + '/' + name + '"',
   )
@@ -161,6 +170,8 @@ install_man(
   'src/grep/grep.1',
   'src/find/find.1',
   'src/xargs/xargs.1',
+  'src/pci/lspci.8',
+  'src/pci/setpci.8',
 )
 
 # --- Gzip shell script utilities ---
@@ -182,7 +193,7 @@ endforeach
 test_env = environment()
 test_env.set('VX', vx.full_path())
 
-foreach t : ['test_patch', 'test_diff', 'test_cmp', 'test_diff3', 'test_sdiff', 'test_which', 'test_gzip', 'test_grep', 'test_find', 'test_xargs']
+foreach t : ['test_patch', 'test_diff', 'test_cmp', 'test_diff3', 'test_sdiff', 'test_which', 'test_gzip', 'test_grep', 'test_find', 'test_xargs', 'test_lspci', 'test_setpci']
   test(t, find_program('tests/' + t + '.sh'),
     env : test_env,
     depends : vx,