Add a devcontainer on alpine

.devcontainer/r-devel-alpine/Dockerfile

@@ -0,0 +1,22 @@
+FROM docker.io/rhub/r-minimal:devel
+
+RUN apk update \
+  && apk add --no-cache \
+     gcc git musl-dev openmp pkgconf tzdata zlib-dev \
+  && echo 'options("repos"="https://cloud.r-project.org")' >> /usr/local/lib/R/etc/Rprofile.site
+
+ENV TZDIR=/usr/share/zoneinfo
+
+COPY DESCRIPTION .
+
+RUN Rscript -e '                                          \ 
+read.dcf("DESCRIPTION", c("Imports", "Suggests")) |>      \
+  tools:::.split_dependencies() |>                        \
+  names() |>                                              \
+  setdiff(tools:::.get_standard_package_names()$base) |>  \
+  install.packages(repos="https://cloud.r-project.org")   \
+'
+
+# setup cc()
+WORKDIR /root
+COPY .devcontainer/.Rprofile .

.devcontainer/r-devel-alpine/devcontainer.json

@@ -0,0 +1,9 @@
+{
+    "build": { "dockerfile": "Dockerfile", "context": "../.." },
+    "customizations": { "vscode": {
+       "extensions": [
+        "REditorSupport.r",
+        "ms-vscode.cpptools-extension-pack"
+       ]
+    }}
+  }

configure

@@ -34,15 +34,11 @@ else
     NOZLIB=0
     lib=`pkg-config --libs zlib`
     cflag=`pkg-config --cflags zlib`
-    expr -- "$lib" : ".*-lz$" >> config.log  # -- for FreeBSD, #4652
+    echo "$lib" | grep -qE '[-]lz($| )' >> config.log
     if [ $? -ne 0 ]; then
-      expr -- "$lib" : ".*-lz " >> config.log
-      # would use \b in one expr but MacOS does not support \b
-      if [ $? -ne 0 ]; then
-        echo "*** pkg-config is installed and 'pkg-config --exists zlib' succeeds but"
-        echo "*** 'pkg-config --libs zlib' returns '${lib}' which does not include the standard -lz."
-        msg=1
-      fi
+      echo "*** pkg-config is installed and 'pkg-config --exists zlib' succeeds but"
+      echo "*** 'pkg-config --libs zlib' returns '${lib}' which does not include the standard -lz."
+      msg=1
     fi
   fi
 fi

inst/tests/tests.Rraw

@@ -8448,11 +8448,9 @@ baseR = base::order(c(x2,x1,x1,x2))
   # are so relaxed now that they barely testing anything. It appears base R behaviour is undefined in this rare case of identical strings in different encodings.
 test(1590.04, identical(baseR, INT(1,4,2,3)) || identical(baseR, INT(2,3,1,4)) || identical(baseR, 1:4))
 Encoding(x2) = "unknown"
-# TODO(#6350): Decide if this test should be adjusted for Alpine Linux, or just dropped.
-if (!file.exists("/etc/alpine-release")) {
-  test(1590.05, x1!=x2)
-  test(1590.06, forderv(    c(x2,x1,x1,x2)), INT(1,4,2,3))  # consistent with Windows-1252 result, tested further below
-}
+# test(1590.05, x1!=x2) # Skip this test of R's own behavior since R itself does not give platform-consistent results, #6350
+# TODO(#6350): Restore this test. On Alpine, forder() finds this input to be sorted, but we want to be platform-independent.
+if (!file.exists("/etc/alpine-release")) test(1590.06, forderv(    c(x2,x1,x1,x2)), INT(1,4,2,3))  # consistent with Windows-1252 result, tested further below
 baseR = base::order(c(x2,x1,x1,x2))
 test(1590.07, identical(baseR, INT(1,4,2,3)) || identical(baseR, INT(2,3,1,4)) || identical(baseR, 1:4))
 Sys.setlocale("LC_CTYPE", ctype)