[ffigen] Add include path for systems with LLVM 11 (e.g. Debian 11) (#125)

pkgs/ffigen/bin/setup.dart

diff --git a/pkgs/ffigen/bin/setup.dart b/pkgs/ffigen/bin/setup.dart
index edc79e2..9949ebc 100644
--- a/pkgs/ffigen/bin/setup.dart
+++ b/pkgs/ffigen/bin/setup.dart
@@ -10,7 +10,7 @@
 ///
 /// Linux:
 /// ```
-/// clang -I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -lclang -shared -fpic path/to/wrapper.c -o path/to/libwrapped_clang.so
+/// clang -I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -I/usr/lib/llvm-11/include/ -lclang -shared -fpic path/to/wrapper.c -o path/to/libwrapped_clang.so
 /// ```
 /// MacOS:
 /// ```
@@ -39,6 +39,7 @@
   headerIncludes: [
     '-I/usr/lib/llvm-9/include/',
     '-I/usr/lib/llvm-10/include/',
+    '-I/usr/lib/llvm-11/include/',
   ],
 );
 final _windowsOpts = _Options(

pkgs/ffigen/example/libclang-example/pubspec.yaml

diff --git a/pkgs/ffigen/example/libclang-example/pubspec.yaml b/pkgs/ffigen/example/libclang-example/pubspec.yaml
index e1a3cfc..f45148f 100644
--- a/pkgs/ffigen/example/libclang-example/pubspec.yaml
+++ b/pkgs/ffigen/example/libclang-example/pubspec.yaml
@@ -24,7 +24,7 @@
       - '**CXString.h'
       - '**Index.h'
 
-  compiler-opts: '-I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -IC:\Progra~1\LLVM\include -I/usr/local/opt/llvm/include/ -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ -Wno-nullability-completeness'
+  compiler-opts: '-I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -I/usr/lib/llvm-11/include/ -IC:\Progra~1\LLVM\include -I/usr/local/opt/llvm/include/ -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ -Wno-nullability-completeness'
   functions:
     include:
       - 'clang_.*' # Can be a regexp, '.' matches any character.

pkgs/ffigen/test/example_tests/libclang_example_test.dart

diff --git a/pkgs/ffigen/test/example_tests/libclang_example_test.dart b/pkgs/ffigen/test/example_tests/libclang_example_test.dart
index ac3feab..dba380d 100644
--- a/pkgs/ffigen/test/example_tests/libclang_example_test.dart
+++ b/pkgs/ffigen/test/example_tests/libclang_example_test.dart
@@ -27,7 +27,7 @@
     - '**CXString.h'
     - '**Index.h'
 
-${strings.compilerOpts}: '-I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -IC:\Progra~1\LLVM\include -I/usr/local/opt/llvm/include/ -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ -Wno-nullability-completeness'
+${strings.compilerOpts}: '-I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -I/usr/lib/llvm-11/include/ -IC:\Progra~1\LLVM\include -I/usr/local/opt/llvm/include/ -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ -Wno-nullability-completeness'
 ${strings.functions}:
   ${strings.include}:
     - 'clang_.*'

pkgs/ffigen/tool/libclang_config.yaml

diff --git a/pkgs/ffigen/tool/libclang_config.yaml b/pkgs/ffigen/tool/libclang_config.yaml
index 4262736..7be7ec1 100644
--- a/pkgs/ffigen/tool/libclang_config.yaml
+++ b/pkgs/ffigen/tool/libclang_config.yaml
@@ -13,7 +13,7 @@
 description: Holds bindings to LibClang.
 output: 'lib/src/header_parser/clang_bindings/clang_bindings.dart'
 sort: true
-compiler-opts: '-I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -I/usr/local/opt/llvm/include/ -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ -Wno-nullability-completeness'
+compiler-opts: '-I/usr/lib/llvm-9/include/ -I/usr/lib/llvm-10/include/ -I/usr/lib/llvm-11/include/ -I/usr/local/opt/llvm/include/ -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ -Wno-nullability-completeness'
 headers:
   entry-points:
     - 'lib/src/clang_library/wrapper.c'