fix compilation when libtbb installed in /usr/local/include

Author: kevinushey

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: RcppParallel
 Type: Package
 Title: Parallel Programming Tools for 'Rcpp'
-Version: 5.0.0
+Version: 5.0.0-9000
 Authors@R: c(
     person("JJ", "Allaire", role = c("aut"), email = "jj@rstudio.com"),
     person("Romain", "Francois", role = c("aut", "cph")),

inst/NEWS

@@ -1,3 +1,8 @@
+RcppParallel 5.0.1 (UNRELEASED)
+------------------------------------------------------------------------
+* Fixed compilation when CPPFLAGS = -I/usr/local/include and a version
+  of libtbb is installed there
+
 RcppParallel 5.0.0
 ------------------------------------------------------------------------
 * RcppParallel backend can now be customized with RCPP_PARALLEL_BACKEND

tools/config/configure.R

@@ -21,14 +21,20 @@ broken <-
 if (broken)
    cxxflags <- gsub("-Werror=format-security", "-Wformat -Werror=format-security", cxxflags)
 
+# avoid including /usr/local/include, as this can cause
+# RcppParallel to find and use a version of libtbb installed
+# there as opposed to the bundled version
+cppflags <- read_r_config("CPPFLAGS", envir = NULL)[[1]]
+cppflags <- sub("(?: )?-I/usr/local/include", "", cppflags)
+
 # define the set of flags appropriate to the current
 # configuration of R
 switch(
    cxx,
 
    CXX11 = define(
       CC            = "$(CC)",
-      CPPFLAGS      = "$(CPPFLAGS)",
+      CPPFLAGS      = cppflags,
       CXX11         = "$(CXX11)",
       CXX11FLAGS    = cxxflags,
       CXX11STD      = "$(CXX11STD)",
@@ -37,7 +43,7 @@ switch(
 
    CXX1X = define(
       CC            = "$(CC)",
-      CPPFLAGS      = "$(CPPFLAGS)",
+      CPPFLAGS      = cppflags,
       CXX11         = "$(CXX1X)",
       CXX11FLAGS    = cxxflags,
       CXX11STD      = "$(CXX1XSTD)",
@@ -46,7 +52,7 @@ switch(
 
    CXX = define(
       CC            = "$(CC)",
-      CPPFLAGS      = "$(CPPFLAGS)",
+      CPPFLAGS      = cppflags,
       CXX11         = "$(CXX)",
       CXX11FLAGS    = cxxflags,
       CXX11STD      = "-std=c++0x",