Add all '*.rst' files in docs as a dependency.

The Meson docs are not a fan of this method, but maintaining that
list by hand is too much work and error prone. This does mean that
adding existing .rst file to the docs will not be picked up by the
dependency checking until you re-setup your build dir.

meson.build

@@ -1125,6 +1125,9 @@ if get_option('unit-tests-backends')
 endif
 
 if python.found()
+  find_rst_files = run_command(['find', docs_dir, '-name', '*.rst'])
+  rst_files = find_rst_files.stdout().strip().split('\n')
+
   html_docs = custom_target(
     'html-docs',
     command: [
@@ -1139,6 +1142,7 @@ if python.found()
     ],
     output: 'html-docs',
     console: true,
+    depend_files: rst_files,
   )
 
   docs_tarball = custom_target(
@@ -1161,6 +1165,7 @@ if python.found()
     ],
     output: 'PowerDNS-Authoritative.pdf',
     console: true,
+    depend_files: rst_files,
   )
 
   run_target(

pdns/dnsdistdist/meson.build

@@ -691,6 +691,9 @@ install_data(
 )
 
 if python.found()
+  find_rst_files = run_command(['find', docs_dir, '-name', '*.rst'])
+  rst_files = find_rst_files.stdout().strip().split('\n')
+
   html_docs = custom_target(
     'html-docs',
     command: [
@@ -705,6 +708,7 @@ if python.found()
     ],
     output: 'html-docs',
     console: true,
+    depend_files: rst_files,
   )
 
   docs_tarball = custom_target(
@@ -727,6 +731,7 @@ if python.found()
     ],
     output: 'dnsdist.pdf',
     console: true,
+    depend_files: rst_files,
   )
 
   run_target(

pdns/recursordist/meson.build

@@ -735,6 +735,9 @@ dep_conf_distfile = custom_target(
 )
 
 if python.found()
+  find_rst_files = run_command(['find', docs_dir, '-name', '*.rst'])
+  rst_files = find_rst_files.stdout().strip().split('\n')
+
   html_docs = custom_target(
     'html-docs',
     command: [
@@ -749,6 +752,7 @@ if python.found()
     ],
     output: 'html-docs',
     console: true,
+    depend_files: rst_files,
   )
 
   docs_tarball = custom_target(
@@ -771,6 +775,7 @@ if python.found()
     ],
     output: 'PowerDNS-Recursor.pdf',
     console: true,
+    depend_files: rst_files,
   )
 
   run_target(