rework the libdrm include paths and configure scripts to account for the fact that the libdrm header files are in a different place on BSD distributions

configure.ac

@@ -68,6 +68,24 @@ PKG_CHECK_MODULES(LIBDRM, [libdrm >= 2.4.121])
 PKG_CHECK_MODULES(LIBDRM_AMDGPU, [libdrm_amdgpu >= 2.4.121])
 PKG_CHECK_MODULES(GBM, [gbm])
 
+# Check for DRM header location (Linux uses drm/ subdirectory, BSD may not)
+SAVE_CPPFLAGS="$CPPFLAGS"
+CPPFLAGS="$CPPFLAGS $LIBDRM_CFLAGS $LIBDRM_AMDGPU_CFLAGS"
+# Check for headers with and without drm/ subdirectory
+AC_CHECK_HEADERS([drm_fourcc.h amdgpu_drm.h],
+    [found_drm_headers=yes],
+    [found_drm_headers=no])
+if test "x$found_drm_headers" = "xno"; then
+    # Fallback: check in drm/ subdirectory
+    AC_CHECK_HEADERS([drm/drm_fourcc.h drm/amdgpu_drm.h],
+        [found_drm_headers=yes
+         # Need to add -I flag for drm/ subdirectory
+         drm_incdir="-I\${includedir}/drm"
+         AC_SUBST(DRM_SUBDIR_INCDIR, ["$drm_incdir"])],
+        [AC_MSG_ERROR([libdrm headers not found - libdrm required])])
+fi
+CPPFLAGS="$SAVE_CPPFLAGS"
+
 # Obtain compiler/linker options for the driver dependencies
 PKG_CHECK_MODULES(XORG, [xorg-server >= 25.0.0 xproto fontsproto xf86driproto randrproto renderproto xextproto >= 7.0.99.1 $REQUIRED_MODULES])
 

src/Makefile.am

@@ -34,8 +34,10 @@ AMDGPU_KMS_SRCS=amdgpu_bo_helper.c amdgpu_dri2.c amdgpu_dri3.c amdgpu_drm_queue.
 AM_CFLAGS = \
             @GBM_CFLAGS@ \
             @LIBDRM_AMDGPU_CFLAGS@ \
+            @LIBDRM_CFLAGS@ \
             @XORG_CFLAGS@ \
-            @LIBUDEV_CFLAGS@
+            @LIBUDEV_CFLAGS@ \
+            $(DRM_SUBDIR_INCDIR)
 
 if LIBUDEV
 amdgpu_drv_la_LIBADD += $(LIBUDEV_LIBS)

src/amdgpu_dri3.c

@@ -36,8 +36,8 @@
 #include <errno.h>
 #include <libgen.h>
 #include <string.h>
-#include <drm/drm_fourcc.h>
-#include <drm/amdgpu_drm.h>
+#include <drm_fourcc.h>
+#include <amdgpu_drm.h>
 #include <unistd.h>
 #include <poll.h>
 

src/meson.build

@@ -15,6 +15,20 @@ srcs = [
   'drmmode_display.c',
 ]
 
+# Check for DRM header location (Linux uses drm/ subdirectory, BSD may not)
+drm_args = []
+drm_incdir = libdrm_dep.get_variable(pkgconfig: 'includedir')
+if meson.get_compiler('c').has_header('drm_fourcc.h') and \
+   meson.get_compiler('c').has_header('amdgpu_drm.h')
+  # Headers found without drm/ subdirectory (BSD)
+elif meson.get_compiler('c').has_header('drm/drm_fourcc.h') and \
+     meson.get_compiler('c').has_header('drm/amdgpu_drm.h')
+  # Headers found with drm/ subdirectory (Linux)
+  drm_args = ['-I' + drm_incdir]
+else
+  error('libdrm headers not found - libdrm required')
+endif
+
 amdgpu_drv_libs = [
   fontsproto_dep,
   gbm_dep,
@@ -37,6 +51,7 @@ shared_module(
   srcs,
   include_directories: include_directories('..'),
   dependencies: amdgpu_drv_libs,
+  c_args: drm_args,
   install: true,
   install_dir: join_paths(moduledir, 'drivers'),
   name_prefix: '',