Try to fix MACOS build

Author: msbahal

.gitignore

@@ -4,4 +4,5 @@
 *.jl.*.cov
 *.jl.mem
 
-Manifest.toml
+Manifest.toml
+deps/build.log

Project.toml

@@ -12,6 +12,7 @@ FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
 FixedPointNumbers = "53c48c17-4a7d-5ca2-90c5-79b7896eea93"
 GeometryTypes = "4d00f742-c7ba-57c2-abde-4428a4b178cb"
 Mmap = "a63ad114-7e13-5084-954f-fe012c677804"
+Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 
 [compat]

deps/build.jl

@@ -0,0 +1,25 @@
+@info "Downloading LasTools"
+import Pkg
+if Sys.isapple()
+    Pkg.add("LibGit2")
+    using LibGit2
+    resource_path = joinpath(dirname(@__DIR__), "resources")
+    lastools_path = joinpath(dirname(@__DIR__), "LAStools")
+    lastools_build_path = joinpath(lastools_path, "build")
+    lastools_install_path = joinpath(lastools_build_path, "install")
+    lastools_executable_path = joinpath(lastools_install_path, "bin")
+    if !isdir(lastools_path)
+        LibGit2.clone("https://github.com/LAStools/LAStools", lastools_path)
+    end
+
+    mkpath(lastools_build_path)
+    cd(lastools_build_path)
+    run(`cmake -DCMAKE_INSTALL_PREFIX=$(lastools_install_path) ../`)
+    run(`cmake --build . --target install --config Release`)
+
+    # find the las executable
+    laszip_executables = filter(x -> startswith(x, "laszip"), readdir(lastools_executable_path))
+    length(laszip_executables) == 0 && error("Unable to build a laszip executable for $(Sys.MACHINE)") 
+    cp(joinpath(lastools_executable_path, laszip_executables[1]), joinpath(resource_path, "laszip"), force=true)
+    rm(lastools_path, recursive=true)
+end

resources/laszip

@@ -3,10 +3,8 @@ using Mmap
 function get_laszip_executable_path()
     if Sys.iswindows()
         return joinpath(dirname(@__DIR__), "resources", "laszip.exe")
-    elseif Sys.islinux()
+    else # point to the linux build of the executable
         return joinpath(dirname(@__DIR__), "resources", "laszip")
-    else
-        error("LasIO  with ZIP functionality is only suported for windows and linux!")
     end
 end