diff --git a/lib/.gitignore b/lib/.gitignore
index e776bc899d..0f0bcd6465 100644
--- a/lib/.gitignore
+++ b/lib/.gitignore
@@ -7,3 +7,4 @@ curl_config.h
 curl_config.h.in
 libcurl.vers
 libcurl_unity.c
+unitprotos.h
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 19db59f9e6..9b0fda5409 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -49,6 +49,14 @@ if(CURL_BUILD_TESTING)
   # There is plenty of parallelism when building the testdeps target.
   # Override the curlu batch size with the maximum to optimize performance.
   set_target_properties(curlu PROPERTIES UNITY_BUILD_BATCH_SIZE 0 C_CLANG_TIDY "")
+
+  add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/unitprotos.h"
+    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+    COMMAND ${PERL_EXECUTABLE} "${PROJECT_SOURCE_DIR}/scripts/extract-unit-protos"
+      ${CSOURCES} > "${CMAKE_CURRENT_BINARY_DIR}/unitprotos.h"
+    DEPENDS "${PROJECT_SOURCE_DIR}/scripts/extract-unit-protos" ${CSOURCES}
+    VERBATIM)
+  add_custom_target(curlu-unitprotos ALL DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/unitprotos.h")
 endif()
 
 ## Library definition
diff --git a/lib/Makefile.am b/lib/Makefile.am
index d43d54979a..75fbbdf4b9 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -39,6 +39,10 @@ lib_LTLIBRARIES = libcurl.la
 
 if BUILD_UNITTESTS
 noinst_LTLIBRARIES = libcurlu.la
+
+# generate a file with "private" prototypes for unit testing
+UNITPROTOS = unitprotos.h
+
 else
 noinst_LTLIBRARIES =
 endif
@@ -88,8 +92,11 @@ CLEANFILES = libcurl_unity.c
 else
 libcurl_la_SOURCES = $(CSOURCES) $(HHEADERS)
 libcurlu_la_SOURCES = $(CSOURCES) $(HHEADERS)
+CLEANFILES =
 endif
 
+CLEANFILES += $(UNITPROTOS)
+
 libcurl_la_CPPFLAGS_EXTRA =
 libcurl_la_LDFLAGS_EXTRA =
 libcurl_la_CFLAGS_EXTRA =
@@ -151,10 +158,21 @@ checksrc:
 if NOT_CURL_CI
 if DEBUGBUILD
 # for debug builds, we scan the sources on all regular make invokes
-all-local: checksrc
+CHECKSOURCES = checksrc
 endif
 endif
 
+all-local: $(CHECKSOURCES) $(UNITPROTOS)
+
+UNIT_V = $(UNITV_$(V))
+UNITV_0 = @echo "  UNITPR  " $@;
+UNITV_1 =
+UNITV_ = $(UNITV_0)
+
+# UNITPROTOS depends on every C file in the lib/ dir
+$(UNITPROTOS): $(CSOURCES)
+	$(UNIT_V)(cd $(srcdir) && @PERL@ ../scripts/extract-unit-protos $(CSOURCES) > $(top_builddir)/lib/$(UNITPROTOS))
+
 # disable the tests that are mostly causing false positives
 TIDYFLAGS := -checks=-clang-analyzer-security.insecureAPI.bzero,-clang-analyzer-security.insecureAPI.strcpy,-clang-analyzer-optin.performance.Padding,-clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling -quiet
 if CURL_WERROR
diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index 0b278e62b0..b4e3c0757b 100644
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -25,7 +25,7 @@
 EXTRA_DIST = coverage.sh completion.pl firefox-db2pem.sh checksrc.pl checksrc-all.sh \
   mk-ca-bundle.pl mk-unity.pl schemetable.c cd2nroff nroff2cd cdall cd2cd managen    \
   dmaketgz maketgz release-tools.sh verify-release cmakelint.sh mdlinkcheck          \
-  CMakeLists.txt pythonlint.sh randdisable wcurl top-complexity
+  CMakeLists.txt pythonlint.sh randdisable wcurl top-complexity extract-unit-protos
 
 dist_bin_SCRIPTS = wcurl
 
diff --git a/scripts/extract-unit-protos b/scripts/extract-unit-protos
new file mode 100755
index 0000000000..9fc6c1b9a3
--- /dev/null
+++ b/scripts/extract-unit-protos
@@ -0,0 +1,90 @@
+#!/usr/bin/env perl
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+# SPDX-License-Identifier: curl
+#
+###########################################################################
+
+sub scanfile {
+    my ($file) = @_;
+    open(F, "<$file") || die "$file failed";
+    while(<F>) {
+        if($_ =~ /^UNITTEST .*\);/) {
+            push @proto, $_;
+            $inc{$file} = 1;
+        }
+    }
+    close(F);
+}
+
+foreach my $f (@ARGV) {
+    scanfile($f);
+}
+
+print <<HEAD
+#ifndef UNITTESTPROTOS_H
+#define UNITTESTPROTOS_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \\| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \\___|\\___/|_| \\_\\_____|
+ *
+ * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ * Generated-by: extract-unit-protos
+ *
+ ***************************************************************************/
+HEAD
+    ;
+
+for my $f (sort keys %inc) {
+    # convert to suitable header file
+    $f =~ s/\.c/.h/; # .h extension
+
+    if(-f $f) {
+        $f =~ s/.*\///; # cut the path off
+        print "#include \"$f\"\n";
+    }
+}
+
+for my $p (@proto) {
+    print $p;
+}
+
+print <<FOOT
+#endif /* UNITTESTPROTOS_H */
+FOOT
+    ;
diff --git a/tests/unit/CMakeLists.txt b/tests/unit/CMakeLists.txt
index f1585f4dda..6ae9c17188 100644
--- a/tests/unit/CMakeLists.txt
+++ b/tests/unit/CMakeLists.txt
@@ -35,10 +35,11 @@ add_custom_command(OUTPUT "${BUNDLE}.c"
   VERBATIM)
 
 add_executable(${BUNDLE} EXCLUDE_FROM_ALL "${BUNDLE}.c")
+add_dependencies(${BUNDLE} curlu-unitprotos)
 add_dependencies(testdeps ${BUNDLE})
 target_link_libraries(${BUNDLE} curlu)
 target_include_directories(${BUNDLE} PRIVATE
-  "${PROJECT_BINARY_DIR}/lib"            # for "curl_config.h"
+  "${PROJECT_BINARY_DIR}/lib"            # for "curl_config.h", "unitprotos.h"
   "${PROJECT_SOURCE_DIR}/lib"            # for "curl_setup.h", curlx
   "${PROJECT_SOURCE_DIR}/tests/libtest"  # for "first.h"
   "${CMAKE_CURRENT_SOURCE_DIR}"          # for the generated bundle source to find included test sources
diff --git a/tests/unit/unit1300.c b/tests/unit/unit1300.c
index d86fac54d5..bdc6b0162b 100644
--- a/tests/unit/unit1300.c
+++ b/tests/unit/unit1300.c
@@ -24,8 +24,7 @@
 #include "curlcheck.h"
 
 #include "llist.h"
-
-UNITTEST void Curl_node_uremove(struct Curl_llist_node *, void *);
+#include "unitprotos.h"
 
 static void test_Curl_llist_dtor(void *key, void *value)
 {
diff --git a/tests/unit/unit1395.c b/tests/unit/unit1395.c
index abb22a4370..7c09b3b78a 100644
--- a/tests/unit/unit1395.c
+++ b/tests/unit/unit1395.c
@@ -22,11 +22,8 @@
  *
  ***************************************************************************/
 #include "curlcheck.h"
-
-/* copied from urlapi.c */
-extern int dedotdotify(const char *input, size_t clen, char **out);
-
 #include "memdebug.h"
+#include "unitprotos.h"
 
 static CURLcode test_unit1395(char *arg)
 {
diff --git a/tests/unit/unit3212.c b/tests/unit/unit3212.c
index f53c1d6c15..1226a6b6fa 100644
--- a/tests/unit/unit3212.c
+++ b/tests/unit/unit3212.c
@@ -26,8 +26,7 @@
 #include "urldata.h"
 #include "uint-table.h"
 #include "curl_trc.h"
-
-UNITTEST void Curl_uint_tbl_clear(struct uint_tbl *tbl);
+#include "unitprotos.h"
 
 #define TBL_SIZE    100
 
diff --git a/tests/unit/unit3213.c b/tests/unit/unit3213.c
index bb5738d2fb..f59ad5a9cf 100644
--- a/tests/unit/unit3213.c
+++ b/tests/unit/unit3213.c
@@ -26,8 +26,7 @@
 #include "urldata.h"
 #include "uint-spbset.h"
 #include "curl_trc.h"
-
-UNITTEST void Curl_uint_spbset_clear(struct uint_spbset *bset);
+#include "unitprotos.h"
 
 static void check_spbset(const char *name, const unsigned int *s, size_t slen)
 {