Add cImport for multiple headers

tests/rsa.nim

@@ -0,0 +1,42 @@
+import os
+import strutils
+
+import nimterop/[build, cimport]
+
+setDefines(@["cryptoStd"])
+getHeader("openssl/crypto.h")
+
+const
+  basePath = cryptoPath.parentDir
+  FLAGS {.strdefine.} = ""
+
+cPlugin:
+  import strutils
+
+  proc onSymbol*(sym: var Symbol) {.exportc, dynlib.} =
+    sym.name = sym.name.strip(chars = {'_'}).replace("__", "_")
+
+    if sym.name in [
+      "AES_ENCRYPT", "AES_DECRYPT",
+      "BIO_CTRL_PENDING", "BIO_CTRL_WPENDING",
+      "BN_F_BNRAND", "BN_F_BNRAND_RANGE",
+      "CRYPTO_THREADID",
+      "EVP_CIPHER",
+      "OPENSSL_VERSION",
+      "PKCS7_ENCRYPT", "PKCS7_STREAM",
+      "SSL_TXT_ADH", "SSL_TXT_AECDH", "SSL_TXT_kECDHE"
+    ]:
+      sym.name = "C_" & sym.name
+
+cOverride:
+  proc OPENSSL_die*(assertion: cstring; file: cstring; line: cint) {.importc.}
+
+cImport(@[
+  basePath / "rsa.h",
+  basePath / "err.h",
+], recurse = true, flags = "-f:ast2 -s " & FLAGS)
+
+{.passL: cryptoLPath.}
+
+OpensslInit()
+echo $OPENSSL_VERSION_TEXT