fix bundled tbb build issues on macos

- disable oneTBB's automatic hwloc search, so the optional tbbbind
  library is no longer built; its link fails on the CRAN macOS machines,
  where a static hwloc is discoverable via pkg-config but its required
  frameworks are not on the link line

- build the bundled oneTBB with __TBB_RESUMABLE_TASKS_USE_THREADS on
  macOS, avoiding the deprecated ucontext APIs (getcontext, swapcontext,
  makecontext)

Author: kevinushey

NEWS.md

@@ -1,5 +1,14 @@
 # RcppParallel (development version)
 
+* When building the bundled copy of oneTBB, RcppParallel no longer searches
+  for hwloc, and so no longer tries to build the optional 'tbbbind' library.
+  This fixes build failures on machines where a static hwloc library is
+  discoverable via pkg-config, as on the CRAN macOS machines.
+
+* On macOS, the bundled copy of oneTBB is now built with
+  `__TBB_RESUMABLE_TASKS_USE_THREADS`, avoiding use of the deprecated
+  ucontext APIs (`getcontext`, `swapcontext`, `makecontext`).
+
 
 # RcppParallel 6.0.0
 

src/install.libs.R

@@ -116,12 +116,23 @@ useBundledTbb <- function() {
    prependFlags("CPPFLAGS", "CFLAGS")
    prependFlags("CPPFLAGS", "CXXFLAGS")
 
+   # the ucontext APIs (getcontext, swapcontext, ...) are deprecated on macOS,
+   # so use the threads-based coroutine implementation for resumable tasks
+   if (Sys.info()[["sysname"]] == "Darwin") {
+      flags <- c(Sys.getenv("CXXFLAGS"), "-D__TBB_RESUMABLE_TASKS_USE_THREADS=1")
+      setenv("CXXFLAGS", flags[nzchar(flags)])
+   }
+
    cmakeFlags <- c(
       forwardEnvVar("CC", "CMAKE_C_COMPILER"),
       forwardEnvVar("CXX", "CMAKE_CXX_COMPILER"),
       forwardEnvVar("CFLAGS", "CMAKE_C_FLAGS"),
       forwardEnvVar("CXXFLAGS", "CMAKE_CXX_FLAGS"),
       forwardEnvVar("CMAKE_BUILD_TYPE", "CMAKE_BUILD_TYPE"),
+      # tbbbind requires hwloc, and hwloc's pkg-config file doesn't advertise
+      # the macOS frameworks needed when linking it statically; RcppParallel
+      # doesn't use TBB's NUMA APIs, so skip tbbbind altogether
+      "-DTBB_DISABLE_HWLOC_AUTOMATIC_SEARCH=1",
       "-DTBB_TEST=0",
       "-DTBB_EXAMPLES=0",
       "-DTBB_STRICT=0",