add meson build file

.clang-format

+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: true
+AlignEscapedNewlinesLeft: false
+AlignOperands: true
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: true
+AllowShortCaseLabelsOnASingleLine: true
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: true
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterFunction: true
+  AfterClass: true
+  AfterControlStatement: true
+  AfterEnum: false
+  AfterNamespace: true
+  AfterStruct: true
+  AfterUnion: true
+  BeforeCatch: true
+  BeforeElse: true
+BinPackArguments: true
+BinPackParameters: true
+BreakBeforeBinaryOperators: All
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: true
+BreakStringLiterals: true
+ColumnLimit: 100
+CommentPragmas: '^ IWYU pragma:'
+ConstructorInitializerAllOnOneLineOrOnePerLine: false
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: true
+DisableFormat: false
+ExperimentalAutoDetectBinPacking: false
+IndentCaseLabels: true
+IndentWidth: 4
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+Language: Cpp
+MaxEmptyLinesToKeep: 4
+NamespaceIndentation: Inner
+PenaltyBreakBeforeFirstCallParameter: 19
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 60
+PointerAlignment: Left
+ReflowComments: true
+SpaceAfterTemplateKeyword: true
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles: false
+SpacesInCStyleCastParentheses: false
+SpacesInContainerLiterals: false
+SpacesInParentheses: true
+SpacesInSquareBrackets: true
+Standard: Cpp11
+TabWidth: 4
+UseTab: Never

main.cpp

+int main(int argc, char **argv)
+{
+    return 0;
+}

meson.build

+project('txt2pcd', 'cpp', default_options: ['cpp_std=c++2a'])
+
+pcl_version = get_option('pcl_version')
+
+pcl_io_dep = dependency('pcl_io-@0@'.format(pcl_version),
+                        required: true)
+
+executable('txt2pcd', sources: files(['main.cpp']),
+           dependencies: [pcl_io_dep])
+

meson_options.txt

+option('pcl_version', type: 'string', value: '1.9', description : 'Set the pointclouds library version to link')