adapted from openssl by @jeroen

src/Makevars.in

@@ -1,7 +1,9 @@
 PKG_CPPFLAGS = @cflags@
-PKG_LIBS = `$(R_HOME)/bin/Rscript -e "Rcpp:::LdFlags()"` -lz  @libs@
+PKG_LIBS = -lz @libs@
 
 all: clean
 
+$(SHLIB): $(OBJECTS)
+
 clean:
 	rm -f $(OBJECTS) $(SHLIB)

src/Makevars.win

@@ -1,11 +1,23 @@
-VERSION=1.1.1k
-PKG_CPPFLAGS= -I../windows/openssl-$(VERSION)/include
-PKG_LIBS = -L../windows/openssl-$(VERSION)/lib${R_ARCH}${CRT} -lz -lcrypto -lws2_32 -lcrypt32
+RWINLIB = ../windows/libssl
+TARGET = lib$(subst gcc,,$(COMPILED_BY))$(R_ARCH)
+PKG_CPPFLAGS = -I$(RWINLIB)/include -DOPENSSL_SUPPRESS_DEPRECATED
 
-all: clean winlibs
+PKG_LIBS = \
+	-L$(RWINLIB)/$(TARGET) \
+	-L$(RWINLIB)/lib \
+	-lssl -lcrypto -lz -lws2_32 -lcrypt32
+
+#all: clean
+all: $(SHLIB)
+
+$(OBJECTS): winlibs
+
+$(SHLIB): $(OBJECTS)
+
+winlibs:
+	"${R_HOME}/bin${R_ARCH_BIN}/Rscript.exe" "../tools/winlibs.R"
 
 clean:
 	rm -f $(SHLIB) $(OBJECTS)
 
-winlibs:
-	"${R_HOME}/bin${R_ARCH_BIN}/Rscript.exe" "../tools/winlibs.R" $(VERSION)
+.PHONY: all clean winlibs

tools/winlibs.R

@@ -1,10 +1,18 @@
-# Build against mingw-w64 build of openssl
-VERSION <- commandArgs(TRUE)
-if (!file.exists(sprintf("../windows/openssl-%s/include/openssl/ssl.h", VERSION))){
-  if (getRversion() < "3.3.0") setInternet2()
-  download.file(sprintf("https://github.com/rwinlib/openssl/archive/v%s.zip", VERSION),
-                "lib.zip", quiet = TRUE)
+if(!file.exists("../windows/libssl/include/openssl/pem.h")){
+  unlink("../windows", recursive = TRUE)
+  url <- if(grepl("aarch", R.version$platform)){
+    "https://github.com/r-windows/bundles/releases/download/openssl-3.1.2/openssl-3.1.2-clang-aarch64.tar.xz"
+  } else if(grepl("clang", Sys.getenv('R_COMPILED_BY'))){
+    "https://github.com/r-windows/bundles/releases/download/openssl-3.1.2/openssl-3.1.2-clang-x86_64.tar.xz"
+  }  else if(getRversion() >= "4.2") {
+    "https://github.com/r-windows/bundles/releases/download/openssl-3.1.2/openssl-3.1.2-ucrt-x86_64.tar.xz"
+  } else {
+    "https://github.com/rwinlib/openssl/archive/v3.1.1.tar.gz"
+  }
+  download.file(url, basename(url), quiet = TRUE)
   dir.create("../windows", showWarnings = FALSE)
-  unzip("lib.zip", exdir = "../windows")
-  unlink("lib.zip")
+  untar(basename(url), exdir = "../windows", tar = 'internal')
+  unlink(basename(url))
+  setwd("../windows")
+  file.rename(list.files(), 'libssl')
 }