Fix building under wasm/webr (#237)

* Fix building under wasm/webr

* Update ldflags for wasm

Author: andrjohns

R/tbb.R

@@ -110,6 +110,10 @@ tbbLdFlags <- function() {
    # shortcut if TBB_LIB defined
    tbbLib <- Sys.getenv("TBB_LINK_LIB", Sys.getenv("TBB_LIB", unset = TBB_LIB))
    if (nzchar(tbbLib)) {
+      if (R.version$os == "emscripten") {
+         fmt <- "-L%1$s -l%2$s"
+         return(sprintf(fmt, asBuildPath(tbbLib), TBB_NAME))
+      }
       fmt <- "-L%1$s -Wl,-rpath,%1$s -l%2$s -l%3$s"
       return(sprintf(fmt, asBuildPath(tbbLib), TBB_NAME, TBB_MALLOC_NAME))
    }

src/install.libs.R

@@ -30,6 +30,10 @@
       Darwin  = "^libtbb.*\\.dylib$",
       "^libtbb.*\\.so.*$"
    )
+   # WASM only supports static libraries
+   if (R.version$os == "emscripten") {
+      shlibPattern <- "^libtbb.*\\.a$"
+   }
 
    if (!nzchar(tbbLib)) {
 
@@ -114,6 +118,15 @@ useBundledTbb <- function() {
       ".."
    )
 
+   if (R.version$os == "emscripten") {
+      cmakeFlags <- c(
+         "-DEMSCRIPTEN=1",
+         "-DTBBMALLOC_BUILD=0",
+         "-DBUILD_SHARED_LIBS=0",
+         cmakeFlags
+      )
+   }
+   
    writeLines("*** configuring tbb")
    owd <- setwd("tbb/build-tbb")
    output <- system2(cmake, shQuote(cmakeFlags), stdout = TRUE, stderr = TRUE)
@@ -145,6 +158,11 @@ useBundledTbb <- function() {
       "^libtbb.*\\.so.*$"
    )
 
+   # WASM only supports static libraries
+   if (R.version$os == "emscripten") {
+      shlibPattern <- "^libtbb.*\\.a$"
+   }
+   
    tbbFiles <- list.files(
       file.path(getwd(), "tbb/build-tbb"),
       pattern = shlibPattern,

tools/config/configure.R

@@ -238,13 +238,18 @@ pkgLibs <- if (!is.na(tbbLib)) {
    NULL
 
 } else {
-   
-   c(
-      "-Wl,-Ltbb/build/lib_release",
-      "-l$(TBB_NAME)",
-      "-l$(TBB_MALLOC_NAME)"
-   )
-   
+   if (R.version$os == "emscripten") {
+      c(
+         "-Wl,-Ltbb/build/lib_release",
+         "-l$(TBB_NAME)"
+      )
+   } else {
+      c(
+         "-Wl,-Ltbb/build/lib_release",
+         "-l$(TBB_NAME)",
+         "-l$(TBB_MALLOC_NAME)"
+      )
+   }
 }